Talk to her about this if she ever becomes your girlfriend.

I went to a small college and I get it (it gets fucking insane how often you discover you are sharing partners with someone else and it is insane how hard it is to avoid certain people given that everyone knows everyone). I ultimately decided to date outside the college (and that is doable/ something to consider) BUT I also think it is worth noting that you are jumping the gun a little bit here regarding this particular situation.

She isn't your girlfriend yet. If she does become a partner then presumably you've gotten to a level where you can trust her and communicate with her. At that point you can talk to her about the fact that this happened three times, that you have some trust issues around this issue and around cheating in general, around these guys in particular, etc. and agree as partners on how to mitigate those anxieties and deal with them in an appropriate way. But you aren't there yet. Get to know her (if you feel comfortable dating her knowing she is friends with these guys and likely has slept with them), then if you end up in a relationship have a conversation about this and about cheating in general. Even if they are targeting her to try to get her to cheat that doesn't mean she is someone who is willing to cheat on you or okay with cheating. A good and trustworthy partner wouldn't cheat no matter who came on to them or what the context is. You don't want to avoid dating people who know these specific guys to avoid getting cheated on, you want to avoid dating people who will cheat on you in order to avoid getting cheated on.

I'd also suggest getting into therapy (regardless of what you decide to do about this particular crush). It is NOT your fault that your previous partners cheated and there is nothing wrong with you, but what you've experienced would cause anyone to have some trust issues and you can address those now in order to put you in the best position to be in a healthy place moving forward and to be a healthy partner. While you're in college you likely have free access to counseling. That is a great thing to use. In other words, focus on developing the skills to have conversations about trust and honesty, to figure out tools for assessing whether a partner is someone who will cheat or not, to calm your own anxiety when confronted with reminders of past partners who cheated, etc. Therapy can help you avoiding bringing baggage from shitty past relationships into your future relationships and can help you heal the hurt from previous experiences so that you are better able to navigate future challenges.