AVD cross tenant possible?

Hello. We have been running an AVD infrastructure with a single 365 tenant. We have 7 AVDs with a few azure hosted VMs. Now we have acquired 2 separate companies over the past 6 months each in their own o365 tenant. Due to compliance issues we will not be migrating these tenants into ours so they will operate independently from our O365 tenant.

The question is it possible or recommended to allow the users in the other 2 tenants access to our AVD infrastructure? I have been reading the cross-tenant scenarios were not supported but then other sites say it is via separate host pools?

Is this possible? If so will be asking for big problems? Also what about licensing? For instance the other 2 tenants are licensed for business standard. Would these tenants need to upgrade their licenses in some way?

Thanks for any info