UTG definately flopped a flush and is not bluffing, and it is not the nut flush, so you already could be behind, or you could be crushing him. and don't just limit his range to connected suitors. Just because those are the flush draw hands that you would play, passive gambly types of players have K
6
in their range pre.
who knows what SB has, but for the price that you are getting, and as you describe both V's, I am never folding here.