Recordset Navigation Bar

Hi, am trying to set the first page of the Navigation bar from a URL variable, is this possible? Each page contains only 1 large image and a Next/ previous button. This works great but always starts from the first record. It also works if I manually change $pageNum_recordset_name = 0; to $pageNum_recordset_name = 2; however, I need this number to be dynamic , the number "0" could be different each time according to a smaller image clicked on from the previous page(Thumbnails).