M Norton - you might find the below link helpful to answer your questions
https://www.irs.gov/retirement-plans/simple-ira-plan-faqs-establishing-a-simple-ira-plan
Can I contribute to my SIMPLE IRA plan if I maintain another retirement plan?
Generally, you can’t contribute to a SIMPLE IRA plan for a calendar year if you maintain another retirement plan and any of your employees receives an allocation or accrues a benefit under the other plan during that calendar year (the “one-plan requirement”).
However, you can have a SIMPLE IRA plan even though you maintain another retirement plan if:
The other plan is only for employees covered under a collective bargaining agreement, and the SIMPLE IRA plan excludes these employees; or
Your business was part of an acquisition, disposition or similar transaction during the current calendar year or the 2 prior calendar years, and only your separate employees participate in the SIMPLE IRA plan.
If you maintain another retirement plan and one of the exceptions above does not apply, you must correct this mistake.
