There may be several ways to prceed on this.
Interest groups, are a group of people with the same interest and set up a local with the idea of affiliating with a specific Org or looking for an affiliation with a National Org.
Colony can be one of two ways:
Local Org is colonized by a National Org and become members and have a specific time frame to meet certain requirements.
A Nationsl Org comes to a campus to find people interested in their Org. If they find enough, they colonize it and they become members and are given a time frame to attain the set goals.
I think this is pretty much standard among the Greek Orgs.
Best of Luck!!!
