Unfortunately, there's just nowhere to hide near the jump point. It's a tough problem. It's going to be years... literally, years... before we are ready to take these clowns on. We can't hold ourselves in a state of readiness for years, waiting for something that probably isn't going to happen... after all, they've been sitting at that jump point for half a year, and haven't come through it. It looks like they either CAN'T come through it (no jump drive) or are under orders to hold the Groombridge system.
You'll be better employed just getting back to work... finish mapping the Ross 248 system before you leave it, then check out the adjacent systems. If they're adjacent to Ross 248, they might be adjacent to Groombridge, or to wherever these aliens come from. We need to know just how many systems these guys are staking out and claiming.
Well can I at least request to be on one of the ships that kicks these sorry sons of bitches asses back to the primordial hole they came from. I just got my baby girl a horse that needs a new brush you know. I understand Im a geologist, but I can still aim a missile like the best of em.