Data Partitioning in Service Desk

Is it possible to apply partitioning rules for Roles instead of Groups?  In reading the Admin guide it doesn't seem that way:

Enabling data partitioning

You need to specify which customers and support groups you want to apply data partitioning to. You do this using the Administration component.

To enable data partitioning:

1. In the Administration component, expand the User Management tree.

2. Expand the Groups branch, then select the Customer or Support Group folder as required.

3. On the Actions list click Enable Partitioning.

A message box appears advising that if you have a large number of groups, that this may take some

time.

Has anyone done data partitioning for a Role in the system?

Thanks,