Well, if the Krall come within 20 lightyears of the kimo home relay or any attempt on Eden prime is made.

Now, I've done some research and there is a small problem with my setup apparently.
Eden prime and the main mass relay of the exodus cluster are in the same system apparently according to the mass effect wiki.
Now that would mean that either one of the largest Kimo military bases is in the same system as Eden prime, rendering it virtually unasailable unless someone would want to tangle with the entire Kimo fifth fleet (which may be a little inconvenient given what I had planned) or, the Kimo home sector is not in the Kite's nest which raises questions of where it would be then.
Alternatively there is also the third option of saying 'ignore the mass effect wiki' on that one and just say the relay is somewhere else in the exodus cluster.
I may need some input from you guys on how to solve this little conundrum.