accessing one webuser control datalist Itemtemplate lnkbtn to someother webuser control and give the validation

I have a web user control suppose a.ascx there is a datalist template item linkbtn lnktbnA
i am adding the data in that and binding it.
I have a web user control suppose b.ascx there is a btn BB
now i want to check IF there is any item named as Final Page then page redirect to some other page else it show some msg that final page is not available you can't go to next page
I want to check this validation on btn click bb which is in web user control b.ascx
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