Interesting, I have the same problem you have with my local club. The master's and teams older than that are great, but there is no organization by anyone for an open team. If it happens it's usually just luck. But I suspect that a lot of the guys who are inthe open division may just have more stuff going on with young kids/family than some of the “older” guys do?
Let me know how your efforts go and if you have any good ideas for recruiting younger runners.