You can do this using a simple macro, The one I have written assumes that you want it to print from cell A1 to the occurence of "99" in the sheet.
Sub SetPrtRng()
Cells.Select
Selection.Find(What:="99", After:=ActiveCell, LookIn:=xlFormulas, LookAt _
:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, MatchCase:= _
False).Activate
Rng = "A1:" & ActiveCell.Address
ActiveSheet.PageSetup.PrintArea = Rng
End Sub