If you already have a group that controls access to BPT then you would look at the members of the group to see who has access.

If you are trying to find out what groups have acces to the BPT module then you would go into customization and look under module access and the groups with Components checked would have access.

If you are trying to track BPT license usage then you would go into site admin click on Site Analysis create a filter for Business Components

There are no built-in reports that would accomplish what you are wanting to do. You could try and create a Business View Excel Report or Excel Report that would pull the needed information from the project database.

To use Excel Reports you will need to add the site parameter ENABLE_CREATE_LEGACY_EXCEL_REPORT and set it's value to Y since these reports are disabled by default.

The Administrator Guide has the information on Business Views and the User Guide will have information on using Excel Reports.