How do you know it's time to let someone go?

I have been best friends with someone who I'll call W for a year and since then of two months ago, another person, B, has joined the picture. B was jealous of W and I being so close and would kind of fight him for me and I confronted him about it, telling him that he's too new to be saying stuff like this, he doesn't even know W (he was telling me bad things regarding our age difference). That has since then passed, but I had marked it as an uncool bit about B, he starts fights.

B quickly becomes a part of W and I's life as he always wants to be around. This goes on for about a month until W comes to me and tells me he needs to talk about B. I ask him why and he tells me that because he's about to "cut him and I off." I was very shocked by this and listened to what he had to say. B would not leave W alone, because everytime he wanted to get onto his console to play a game, B was "waiting for him." W wanted his alone time "because I'm an introvert," but B was getting in the way of that. I talked to him about it and told him to leave him alone. I told B that we were done, we can't be friends anymore if this is going to keep happening, but he managed to get his way back in.

I realized I needed a break from B and did just that. During that time, B would ask W "what do I do about Verklighet" and W warned him that if he asked him one more time about me, he is going to cut him off, or ignore him. He got there and B came to me after W told me what happened. I told B that he was warned and that he needed to leave him alone.

This morning, B asks me if he should even try to be friends with W anymore and I tell him to take a hint and leave him alone. I'm very irritated with him now. W warned me that I should drop him before things get out of hand, but I guess I'm lonely and enjoy B's company. It's been very conflicting with me today.

On Saturday, I was about to play a game with my brother, B, and W, and I told W that B was going to be playing with us, "if that's okay with you." He told me no and said that he'd play later. He also told me that "dude's a stalker," and that made me rethink every other thing that I would tell B. I'm having problems with B but I shouldn't tell him that because it could fuel whatever it happening and he doesn't need to know what I'm thinking, bla bla bla.

You should know that all of this is happening online. We all play Xbox together. We are all treating this as if it was real life and I'm taking it all very seriously. If you have more questions, please ask, I wrote this all out on a time crunch, but I wanted to get this out. It's out now.

I told a friends about this problem this morning and he told me I should try and find a new squad altogether, but I really would like to keep W around, I like him, and I trust he knows what he's talking about, he's like my mentor (he is a lot older than me). I don't know what to do. Do I wait it out and see what happens? Do I take action and boot one or more people away? I don't want B to act up again if he does, because if it gets to W, something bad may happen. I don't think I can leave this problem alone anymore.

Nothing is happening now, I guess, but I sure wouldn't feel this way if there was never any drama in the first place when B was introduced.