diff --git a/k4Gen/src/components/GenEventFilter.cpp b/k4Gen/src/components/GenEventFilter.cpp
index 4bb5fdc..7bea6d8 100644
--- a/k4Gen/src/components/GenEventFilter.cpp
+++ b/k4Gen/src/components/GenEventFilter.cpp
@@ -10,6 +10,9 @@
 // Datamodel
 #include "edm4hep/MCParticleCollection.h"
 
+// ROOT
+#include "TInterpreter.h"
+
 DECLARE_COMPONENT(GenEventFilter)
 
 GenEventFilter::GenEventFilter(
@@ -39,13 +42,41 @@ StatusCode GenEventFilter::initialize() {
 
   m_eventProcessor = service("ApplicationMgr");
 
+  {
+    bool success = gInterpreter->Declare("#include \"edm4hep/MCParticleCollection.h\"");
+    if (!success) {
+      error() << "Unable to find edm4hep::MCParticleCollection header file!" << endmsg;
+      return StatusCode::FAILURE;
+    }
+    debug() << "Found edm4hep::MCParticleCollection header file." << endmsg;
+  }
+
+  {
+    bool success = gInterpreter->Declare("bool filterRule(const edm4hep::MCParticleCollection& inColl){return inColl.size() > 1000;}");
+    if (!success) {
+      error() << "Unable to compile filter rule!" << endmsg;
+      return StatusCode::FAILURE;
+    }
+    debug() << "Filter rule compiled successfully." << endmsg;
+  }
+
+  {
+    enum TInterpreter::EErrorCode err = TInterpreter::kProcessing;
+    m_filterRulePtr = (bool (*)(const edm4hep::MCParticleCollection*)) gInterpreter->ProcessLineSynch("&filterRule", &err);
+    if (err != TInterpreter::kNoError) {
+      error() << "Unable to obtain filter rule pointer!" << endmsg;
+      return StatusCode::FAILURE;
+    }
+    debug() << "Filter rule pointer obtained successfully." << endmsg;
+  }
+
   return StatusCode::SUCCESS;
 }
 
 StatusCode GenEventFilter::execute() {
   const edm4hep::MCParticleCollection* inParticles = m_inColl.get();
   m_nEventsSeen++;
-  bool accept = true;
+
   /*
   int cntr = 0;
   for (auto ptc : (*inParticles)) {
@@ -62,15 +93,7 @@ StatusCode GenEventFilter::execute() {
   */
 
 
-  Gaudi::Property<int> go;
-  go.assign(m_property->getProperty("Go"));
-  debug() << "Go: " << go << endmsg;
-
-  if (inParticles->size() < 1000) {
-    accept = false;
-  }
-
-  if (!accept) {
+  if (!(*m_filterRulePtr)(inParticles)) {
     debug() << "Skipping event..." << endmsg;
 
     {
@@ -97,9 +120,13 @@ StatusCode GenEventFilter::execute() {
           << endmsg;
   debug() << "Remaining number of event to generate: "
           << m_nEventsTarget - m_nEventsAccepted << endmsg;
-  debug() << "Number of events seen: " << m_nEventsSeen << endmsg;
+  debug() << "Number of events seen so far: " << m_nEventsSeen << endmsg;
 
   return StatusCode::SUCCESS;
 }
 
-StatusCode GenEventFilter::finalize() { return GaudiAlgorithm::finalize(); }
+StatusCode GenEventFilter::finalize() {
+  debug() << "Number of events seen: " << m_nEventsSeen << endmsg;
+
+  return GaudiAlgorithm::finalize();
+}
diff --git a/k4Gen/src/components/GenEventFilter.h b/k4Gen/src/components/GenEventFilter.h
index ea48fe7..cb1af65 100644
--- a/k4Gen/src/components/GenEventFilter.h
+++ b/k4Gen/src/components/GenEventFilter.h
@@ -55,6 +55,8 @@ class GenEventFilter : public GaudiAlgorithm {
   SmartIF<IIncidentSvc> m_incidentSvc;
   /// Pointer to the event processor.
   SmartIF<IEventProcessor> m_eventProcessor;
+  /// Filter rule pointer.
+  bool (*m_filterRulePtr)(const edm4hep::MCParticleCollection*);
 };
 
 #endif  // GENERATION_GENEVENTFILTER_H