If you say borei pri ha'gafen and drink at least 2 fl. oz. (59 ml) of wine (or grape juice) within 30 seconds, the borei pri ha'gafen will cover all subsequent beverages you drink at about the same time--even if their fore-blessing should be she'hakol.
NoteSaying the after-blessing on the wine/grape juice--if drinking at least 3.3 fl. oz. (99 ml) of the wine/grape juice--covers the water or other beverage that you drank.