How to find number of (gamma, 1n) reactions taking place

I am using a simple geometry where an electron beam hits a target and I am scoring neutron flux using G4MultiFunctionalDetector. It gives me total number of neutrons generated which by in large includes reactions such as (gamma, 1n) (gamma, 2n) (gamma, 3n) etc. Out of these I am only interested in finding out the neutrons that have generated via (gamma, 1n) reaction.
Can I get some help or guidance here?
Any example that I can look at?



you need analyze secondary particles at each step. see Geant4 extended examples, for example, $G4INSTALL/examples/extended/hadronic/Hadr01