BPC Script hierarchy

Hi Experts,

*XDIM_MEMBERSET CLIENTSEG =  BAS(CLIENTSEG_TOTAL)

As per my understanding the above statement restricts the clientseg to clientseg_total base members.

Please help with following questions.

1) Suppose if I have 3 hierarchies for that dimension , and in each hierarchy have differenet set of base memebers for Clientseg_total, then how will the script recognize from which hierarchiey it should consider the base members of clientseg_total.

2) if I want to use the same kind of statement in badi ,could you please help how to wirte that statement inside the badi which solves the above purpose.

Thank you.