Hide Users from Teams Directory

Hi,

I'm currently dealing with a complex issue involving a Microsoft 365 tenant that hosts three different domains. My objective is to restrict users from one domain from being able to see or communicate with users from another domain—specifically within Microsoft Teams chat suggestions.

I’ve configured Address Book Policies (ABPs) for the three domains, and they are working perfectly in Microsoft Exchange. However, the restrictions do not apply in Microsoft Teams.

After contacting Microsoft Support, I was informed that ABPs do not affect Microsoft Teams. They advised that to enforce this kind of separation in Teams, I would need either a Microsoft 365 E5 subscription or the Microsoft 365 E5 Compliance add-on to use Information Barriers (IBs).

My question is:
Is there any alternative way to restrict visibility, communication, and collaboration between defined user groups in Microsoft Teams without upgrading to Microsoft 365 E5 or purchasing the E5 Compliance add-on

Any guidance or workaround would be greatly appreciated.

Thanks