If the system was built from the group up, even in the old engine (new is obviously better) it could also include instanced systems; like the time bubble we have for larger fights now (at the discretion of the SM), those could be used to handle systems separate from each other if no jumps are present, and completely ignore them if no one is in them.
Right now, that is unfeasible. What I'd like, though, it a race limit that prevents NPRs from generating further NPRs after a certain margin.
In addition to that, a system limit switch might also be a nice bonus.