Allow Guest access to custom domains on Tenant level
Guest access should be restricted for customized domains on Tenant level in Microsoft Teams. Right now it is allowing the user to send request to all the domains with guest access. My companies are involved in their compliance and require to allow Guest access to limited domains only.
You should be bale to already do this here: https://docs.microsoft.com/en-us/azure/active-directory/b2b/allow-deny-list