Indian Tribe's Controlled Group?

[Guest eba]

An Indian tribe has a prototype 401(k) (non-standard) and would like to allow an entity that has a close affiliation with the tribe, but which has a different EIN, become a participating employer under the adoption agreement. If they were affiliated corporations, the controlled group rules would apply and the affiliate could sign on. What kind of analysis would apply to a tribe for these purposes?

[mbozek]

The only rules that apply are the controlled group and affiliated service group rules that apply to profit making entities.