Not to but in (an SEDiv guy), but our SIC (Southeast Invitational Challenge) is a pretty big deal. Here's how we do it:

a. Invitation only, but invitation is sent to any one who ran at least 3 SARRC events in a season. I think this is the right kind of threshold -- doesn't keep anyone out on points, just a participation requirement.

b. Here's teh kicker: the SIC "pays" double points over a regular SARRC race. Taht's a pretty big deal and often results in the championship being decided at teh SARRC.

Works for us.