Retrieve information on the struck nucleon inside nucleus

Dear Geant4 experts,

I am simulating pi+ argon interactions. I am able to save the information of all the secondary particles generated from the pion argon interaction. Is there a way to retrieve the initial momentum information of the struck nucleon inside the argon nucleus for the inelastic scattering? This is essentially the Fermi momentum. Thanks.

Best regards,

I am not sure this information (which will be internal to whatever hadronic model is involved, such as Bertini or INCL++ or BinaryCascade) is exposed in a way that you can get to it. Even getting the struck nucleus is awkward.