GCP Resource hierarchy - Single folder with multitenant projects, how to isolate them

[dheerajpanyam]

I am trying to figure out how to achieve multi tenancy with isolation / controlled IAM access  in a GCP Resource hierarchy with a single folder containing multiple customer projects. Goal is to isolate all projects from an IAM perspective. Image a folder with customer projects , project-A, project-B and project-C which are all customer projects. I want to be able to allow only google group say customer1@xyz.com    access to project-A only, another google group say customer2@xyz.com access to project-B only and so on.