Link User Group members to a new request

We have a request intake form within Clarizen that assigns the request to a specific user group. Because we are using enhanced permissions, the members of the assigned user group cannot see the request unless they have a specific role (ie, Assigned To). I am trying to link the group members of the assigned user group as Team Members of the new request, but am having issues with finding the correct functions to do so. I started building a workflow to update all new requests:

New Item: Case Team

$Case = CurrentObject()

$TeamMember = this is where I'm stuck. I don't want to name a specific user; rather I want to pull all users within the user group linked to that new request

Any help would be much appreciated. Thank you!!