Group Chart and Company code ??

hey,

i was working on 2 company codes with 2 chrts.... Cocd BHEL = Chsrt CHBE

Cocd VBP = Chart RK

group chart is = GROU

now CHBE and RK has elements in it (accounts) and assigned to a company code... what bout GROU... is it mandatory to assign this to any company code ?? how to create accounts in account groups of GROU...???

plz help me...

Bye...

Suresh