Hello kuber2vedi,
Sadly, instead of solving this we migrate to the S32K family, the project we are working on small demonstration and we didn't have strickt requirement on using specific MCU family,
But while I was awaiting reply I was converted the simulink model into the C code, The code responsible from FCAN sending & receiving is easily readable,
I think it's possible to declare a variable and use that in the FCAN functions in C code
But I didn't try that yet
Thanks