I try to keep my sanity in moba's by muting people early if they become unfriendly in chat. You'd expect not to be grouped again with people you've muted, but I've experienced first hand that this is not the case in Dota 2 (it was a very confusing bit of party chat the first few minutes of the game where I started out with someone I had previously muted...).
Long story short: in HotS, will you be grouped with people you've previously muted? The specific feature I'm talking about is the "Block all communications from this player" button in the tab screen you can get while in a game.