Can you exclude H-2A employees as a class?

Suppose an employer has a plan with 100 otherwise eligible employees, including 10 H2A employees. Can the employer exclude the H-2A employees as a class (will easily pass coverage testing). I'm seeing conflicting information on this - some indicating that under IRCA you cannot exclude them as a class, other information indicating you can. Anyone have any experience with this issue?

If an employer has H-2A employees, the employer likely uses a law firm at least to help on getting approvals, and advise about conditions, for those guest workers.

If whether it is feasible to exclude from a retirement plan the H-2A employees turns on law beyond ERISA and the Internal Revenue Code, it might make sense to put such an other-law question to the lawyers who handle the H-2A matters.

Thanks Peter. I've been in this business a long time, and have never even heard of this issue. 

I worked, as counsel to another law firm, on a situation about H-2A employees.  But I never saw any advice about employment law or immigration law.  The other firm looked to me first, and the facts left no escape from Internal Revenue Code § 410(b).  (Testing was a non-starter.)

Certain visas require that an employer pay the employee a certain (market) rate. Since a retirement contribution is compensation, an exclusion from the plan, especially based on a visa classification, may involve a violation of the compensation rate standards for the visa. This is not my field, so I am not sure that the H-2A visa is subject to the rules. I do not know if retirement plan compensation is part of the compensation under the rules. As noted in another message, these rules are beyond the ERISA realm.

Not my field either but i think IRCA and general employment law prohibit discrimination based on citizenship and immigration status.  Like everyone else is saying seek appropriate counsel