I wanto to remove the buttons in over view page and item assingment block in salec order in sap crm?

HI Team,

I wan to remove the buttons in over view copy button and item assingnment block INSERT ,DELETE,MORE,ADD,MORE in ITEM assingment block based on user groups . i have found the function module as below.Please help how to do it.

BAPI_USER_GET_DETAIL- table activity groups..please help

Thanks

kalpana