How to defend a social position?

Title. I'm in a class right now and I've been getting "louder", so to speak, with increased involvement in projects and leadership roles. It's taken a lot for me to get to this point, but I'm starting to attract unwanted attention.

People are beginning to try and play social games with me and I'm not sure how to respond? Last week a group tried to poach one of my team members, people are constantly trying to talk over me, and I notice at least one person always trying to eavesdrop on my conversations with the professor.

I'm not interested in playing offensively, at least at this point I don't really see the need to. I'm looking to strengthen my position so people lose interest.