Trade Association Profit Sharing Plan

[richard]

Can a trade association provide a profit sharing (or other retirement-type) plan for its members? If so, what are some of the design, administration, legal issues?

In the situation I have in mind, the members are individual business owners (typically with no employees). The trade association is not a union, so a multiemployer plan won't work. I suspect that here a multiple employer plan could potentially apply.

If so, what would be the difference between one multiple employer plan covering participating employers, and having each employer set up separate profit sharing (or DB) plans for himself?

How common are these types of plans? (I remember working on one about 15 years ago, and one key issue was whether or not screw-ups are the individual participating employer level could jeopardize the other participating employers or the overall plan.)

Thanks