Well being an ENFJ myself, I think I can give you some pointers. First of all, I think I understand this whole snowball effect that these people are creating around you. This snowball you are creating is causing you problems. Ok, now captain obvious is done.
What I do in a situation like this is make some time to talk to them one on one. Talk to each of them in private and truly let them know how you feel from the bottom of your heart. Let them know that you do not appreciate this kind of behavior. Let them know that it is not in your best interest to hurt them, but to build them.
One thing I've learned in my life is honesty IS the best policy. The longer this goes on with out anything being done, the harder it will become to break this cycle. The truth hurts, and I've experienced this first hand.
I use to do things that bothered others, and some of them actually had the guts to talk to me one on one about them. At first, I was offended because I was immature. Later on, I realized that those people truly cared for me because they were willing to break me down and help me rebuild myself into a stronger person. Also, a person truly cares when they are willing to hurt you a little in order to help you mature as a person. Today, I love hearing constructive criticism. It still hurts me, but I appreciate it now.
Sometimes a person can be really thickheaded and not truly understand what you are trying to say. It can also be hard when you having a hard time pointing out examples of their problematic behavior. If they can't change their ways when you tell them one on one, you will have to take the next step and point out their actions on the spot. When their snowballing effect is beginning, and only after you have talked to them both on an individual basis, point them out. You can try breaking it up saying you need to talk with them alone, but it may not be that easy. You just might have to say "Listen guys/girls THIS is what I've been talking about, THIS is what needs to STOP."
Again I would try doing things soft at first, but if that doesn't work, you will need to be firm. Sometimes a person just doesn't get it unless you are firm. Let your "No" mean "No". If you say "I can't hang out with you both if you continue this", then you have to mean it. In the worst case scenario, it might just take you not hanging out with them together to make them realize the error of their ways.
If they get offended and blow you off, that is THEIR problem not yours. Maturing is a very difficult thing to accomplish in life and hurt is a part of maturing. Like the statement "No pain no gain", it is true with our emotional selves as well. By breaking down our weaker selves, we can build a stronger house to hold our soul in. This house is the house of maturity which our soul dwells.
I truly hopes this can help you out some. Also, I hope I'm making sense as I can go on and on when I get started. Everybody else's advise looked good to me, so I don't know if I added anything new, but I just wanted to give you my two cent.
Anyways, I truly hope things can work out with you guys/girls.