Is it Possible for a user to have access with multiple tenants at same time

I wanted to know if flowable supports a scenario where access can be given to a user with multiple tenants at the same time. For example, I have 5 Tenants namely A,B,C,D,E. And i have a user “USER1” which wants to have access for Tenant A and Tenant B together only and not have access to C,D,E. Does flowable support this scenario?

No, out of the box. AFAIK.

If you need to support this scenario you can customize flowable. Please keep in mind, UI application are samples how flowable could be used.