Limiting election to one plan type or another (3X plans)

Our organization offers employees 2 short term disability (STD) plans to choose from; STD plan with vendor A or STD plan with vendor B.

Each plan is structured differently and as a result we are looking to configure 2 distinct plan types and event rules for both plans.

STD plan with vendor A has 3 tiers. Employees can elect any level when newly hired, but can only go up one tier during open enrollment. The EOI and Level Rules have been configured accordingly. STD plan with vendor B only has 1 tier and will be associated with a different event rule.

Employees can only choose to enroll with vendor A