Custom screen area for notification

Dear Gurus ,

As per customer requirement I need to create a screen area called Z10 , how can I create the same .I can not use existing 090 / 091 custom screen areas , since I have devoloped the custom screen in screen area 090 as well as 091 but this screen areas are calling in another transactions also (like in IW21)which I must not modify.Please suggest me asap.

Thanks in advance

Anil