I would check/call or possibly check/fold on 4th. 3 of 4 opponents have 2 card flushes with an over card. Even though almost all your cards are live it's a scary situation. Even if only 1 of the 3 potential flushes are actually there on 4th, you're still a dog to 3 opponents going to only to 6th street with this hand situation against this board. I'd have to know where the bet came from to determine if I'd call.

JMO - Knoll