Q. Hi. I was wandering what is the Bracha Acharona when drinking grape juice, plus eating  burekas, plus eating dates or a pomegranate. What Bracha Acharona should I say?
A. If the burekas are mezonos (some are not), you recite one single  brocho, and add all three items consumed, namely; Al Hamichya, Veal Hagefen , Veal Haperos, on that order.
That is when you ate and drank the right amount of each kind. Kezais is about 30 g. Reviis more than 86 cc. or better 130 cc. See Shulchan Aruch (O.H. 208: 12)
Horav Shlomo Miller’s Shlit’a opinion is similar.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a