Adding Permissions to new Roles in a Project

Hello everybody.

I am struggling to add new ACLs to new roles in a project.

My requirement is to add an external user to a project in a new role.

This user should have modify content to any Change Notice and Change Task shared to the project.

Looks like this is possible using "Shared Teams" as per the article below:

https://www.ptc.com/en/support/article/CS199620

I have opened a case with PTC TS but even they are struggling. All internal notes from PTC R&D point to use the shared tams functionalities.

Has anybody implemented Shared Teams to allow/control different ACLs in a Project?

Do you suggest any other way to achieve my requirement?

Thanks!