Dear Corrado,
you need to use if statements
you need to change the variables IARES, IZRES and IISRES on lines 99-101 to the mass, atomic, and isomer numbers of the individual isotopes using code similar to Multiple complex source in Fluka - #2 by horvathd
IPROA, IPROZ and IPROM variables store the values set on the HI-PROPE card in the FLUKA input.
Cheers,
David