diff --git a/MC/config/PWGDQ/external/generator/generator_pythia8Onia_PromptSignals_gaptriggered.C b/MC/config/PWGDQ/external/generator/generator_pythia8Onia_PromptSignals_gaptriggered.C
new file mode 100644
index 000000000..f37e207f4
--- /dev/null
+++ b/MC/config/PWGDQ/external/generator/generator_pythia8Onia_PromptSignals_gaptriggered.C
@@ -0,0 +1,176 @@
+#include "FairGenerator.h"
+#include "Generators/GeneratorPythia8.h"
+#include "Pythia8/Pythia.h"
+#include "TRandom.h"
+
+R__ADD_INCLUDE_PATH($O2DPG_MC_CONFIG_ROOT/MC/config/PWGDQ/EvtGen)
+#include "GeneratorEvtGen.C"
+
+#include <string>
+
+using namespace o2::eventgen;
+
+namespace o2
+{
+namespace eventgen
+{
+
+class GeneratorPythia8OniaPromptSignalsGapTriggered : public o2::eventgen::GeneratorPythia8 {
+public:
+  
+  /// constructor
+  GeneratorPythia8OniaPromptSignalsGapTriggered(int inputTriggerRatio = 5)  {
+
+    mGeneratedEvents = 0;
+    mInverseTriggerRatio = inputTriggerRatio;
+    // define minimum bias event generator
+    auto seed = (gRandom->TRandom::GetSeed() % 900000000);
+    TString pathconfigMB = gSystem->ExpandPathName("${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGDQ/pythia8/generator/pythia8_inel_triggerGap.cfg");
+    pythiaMBgen.readFile(pathconfigMB.Data());
+    pythiaMBgen.readString("Random:setSeed on");
+    pythiaMBgen.readString("Random:seed " + std::to_string(seed));
+    mConfigMBdecays = "";
+    mRapidityMin = -1.;
+    mRapidityMax = 1.;
+    mVerbose = false; 
+  }
+
+  ///  Destructor
+  ~GeneratorPythia8OniaPromptSignalsGapTriggered() = default;
+
+  void addHadronPDGs(int pdg) { mHadronsPDGs.push_back(pdg); };
+
+  void setRapidityRange(double valMin, double valMax)
+  {
+    mRapidityMin = valMin;
+    mRapidityMax = valMax;
+  };
+
+  void setTriggerGap(int triggerGap) {mInverseTriggerRatio = triggerGap;}
+
+  void setConfigMBdecays(TString val){mConfigMBdecays = val;}
+
+  void setVerbose(bool val) { mVerbose = val; };
+
+protected:
+
+bool generateEvent() override {
+  // reset  event
+  bool genOk = false;
+  if (mGeneratedEvents % mInverseTriggerRatio == 0) {
+    bool found = false;
+    while (! (genOk && found)) {
+      /// reset event
+      mPythia.event.reset();
+      genOk = GeneratorPythia8::generateEvent(); 
+      // find the q-qbar or single hadron ancestor
+      found = findHadrons(mPythia.event);
+    }
+    notifySubGenerator(1);
+  } else {
+    /// reset event
+    pythiaMBgen.event.reset();
+    while (!genOk) {
+      genOk = pythiaMBgen.next();
+    }
+    mPythia.event = pythiaMBgen.event;
+    notifySubGenerator(0);
+  }
+  mGeneratedEvents++; 
+  if (mVerbose) { 
+    mOutputEvent.list();
+  }
+  return true;
+}
+
+bool Init() override {
+        
+  if(mConfigMBdecays.Contains("cfg")) {
+    pythiaMBgen.readFile(mConfigMBdecays.Data());	
+  }
+  addSubGenerator(0, "Minimum bias");
+  addSubGenerator(1, "Onia injected");
+	GeneratorPythia8::Init();
+  pythiaMBgen.init();
+  return true;
+} 
+
+// search for the presence of at least one of the required hadrons in a selected rapidity window
+bool findHadrons(Pythia8::Event& event) { 
+   
+  for (int ipa = 0; ipa < event.size(); ++ipa) {
+    
+    auto daughterList = event[ipa].daughterList();
+  
+    for (auto ida : daughterList) {
+      for (int pdg : mHadronsPDGs) {   // check that at least one of the pdg code is found in the event
+        if (event[ida].id() == pdg) {
+          if ((event[ida].y() > mRapidityMin) && (event[ida].y() < mRapidityMax)) {
+            cout << "============= Found jpsi y,pt " <<  event[ida].y() << ", " << event[ida].pT() << endl;
+            std::vector<int> daughters = event[ida].daughterList();
+            for (int d : daughters) {
+              cout << "###### daughter " << d << ": code " << event[d].id() << ", pt " << event[d].pT() << endl;
+            }
+            return true;
+          }
+        }
+      }
+    }
+  }
+
+  return false;
+};
+
+
+private:
+  // Interface to override import particles
+  Pythia8::Event mOutputEvent;
+
+  // Control gap-triggering
+  unsigned long long mGeneratedEvents;
+  int mInverseTriggerRatio;
+  Pythia8::Pythia pythiaMBgen; // minimum bias event  
+  TString mConfigMBdecays;		
+  std::vector<int> mHadronsPDGs;
+  double mRapidityMin; 
+  double mRapidityMax;
+  bool mVerbose;
+};
+
+}
+
+}
+
+// Predefined generators:
+FairGenerator*
+  GeneratorPromptJpsi_EvtGenMidY(int triggerGap, double rapidityMin = -1.5, double rapidityMax = 1.5, bool verbose = false)
+{
+  auto gen = new o2::eventgen::GeneratorEvtGen<o2::eventgen::GeneratorPythia8OniaPromptSignalsGapTriggered>();
+  gen->setTriggerGap(triggerGap);
+  gen->setRapidityRange(rapidityMin, rapidityMax);
+  gen->addHadronPDGs(443);
+  gen->setVerbose(verbose);
+
+  TString pathO2table = gSystem->ExpandPathName("${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGDQ/pythia8/decayer/switchOffJpsi.cfg");
+  gen->readFile(pathO2table.Data());
+  gen->setConfigMBdecays(pathO2table);
+  gen->PrintDebug(true);
+
+  gen->SetSizePdg(1);
+  gen->AddPdg(443, 0);
+
+  gen->SetForceDecay(kEvtDiElectron);
+
+  // set random seed
+  gen->readString("Random:setSeed on");
+  uint random_seed;
+  unsigned long long int random_value = 0;
+  ifstream urandom("/dev/urandom", ios::in|ios::binary);
+  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
+  gen->readString(Form("Random:seed = %llu", random_value % 900000001));
+
+  // print debug
+  // gen->PrintDebug();
+
+  return gen;
+}
\ No newline at end of file
diff --git a/MC/config/PWGDQ/ini/Generator_InjectedPromptJpsiMidy_PythiaOnia_TriggerGap.ini b/MC/config/PWGDQ/ini/Generator_InjectedPromptJpsiMidy_PythiaOnia_TriggerGap.ini
new file mode 100755
index 000000000..139503480
--- /dev/null
+++ b/MC/config/PWGDQ/ini/Generator_InjectedPromptJpsiMidy_PythiaOnia_TriggerGap.ini
@@ -0,0 +1,7 @@
+### The external generator derives from GeneratorPythia8.
+[GeneratorExternal]
+fileName=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGDQ/external/generator/generator_pythia8Onia_PromptSignals_gaptriggered.C
+funcName=GeneratorPromptJpsi_EvtGenMidY(5,-1.5,1.5)
+
+[GeneratorPythia8]
+config=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGDQ/pythia8/generator/pythia8_onia_triggerGap.cfg
diff --git a/MC/config/PWGDQ/pythia8/decayer/switchOffJpsi.cfg b/MC/config/PWGDQ/pythia8/decayer/switchOffJpsi.cfg
new file mode 100644
index 000000000..da279b4aa
--- /dev/null
+++ b/MC/config/PWGDQ/pythia8/decayer/switchOffJpsi.cfg
@@ -0,0 +1,3 @@
+#switch off jpsi decays
+
+443:mayDecay  off	# J/psi
diff --git a/MC/config/PWGDQ/pythia8/generator/pythia8_onia_triggerGap.cfg b/MC/config/PWGDQ/pythia8/generator/pythia8_onia_triggerGap.cfg
new file mode 100644
index 000000000..841f84d70
--- /dev/null
+++ b/MC/config/PWGDQ/pythia8/generator/pythia8_onia_triggerGap.cfg
@@ -0,0 +1,12 @@
+### beams
+Beams:idA 2212			# proton
+Beams:idB 2212 			# proton
+Beams:eCM 13600. 		# GeV
+
+### processes
+SoftQCD:inelastic on		# all inelastic processes
+CharmoniumShower:all = on
+
+### decays
+ParticleDecays:limitTau0 on	
+ParticleDecays:tau0Max 10.