Technically it is possible to assign group COA to an operating COA which is assigned to two company codes where fiscal years are different for both of them. But you need a FSV(Financial statement version) for your group COA to see the balances.
But practically you can't assign these two company codes to single controlling area as the fact that these two company codes have different fiscal year variants.
So, no use finally according to my understanding.
Also, If you are using new gl, then follow sridhar suggestion.
Rgds
Murali. N
