Dear @talktoshubhama,
yes of course it is possible. You have to select HEAVYION in the BEAM card (and in that case the kinetic energy or momentum will be interpreted as per nuclear mass unit). Then you have to add the HI-PROPErt card which allows to set the Z and A of your desired ion. You should also add the PHYSICS cards activating the treatment of coalescence and evaporation of heavy fragments (See the manual).
Remember that if heavy ions are your primary particles you should link the RQMD and DPMJET event generators (linking with ldpmqmd and not lfluka) or, in Flair, run with flukadpm.
Best,
Davide