The Baseline policy actually works based on the Operating system. Hence, you can keep only one baseline policy (gold image) per operating system. In your case, if there are multiple groups like IT/Marketing/Sales having same Operating systems across the orgranization. Probably the only way is to export and save the policy setting for each group like Sales etc., and restore it when you run the policy scan against that particular group.
In other words, first you run a baseline scan for e.g. against "Sales" group. Merge the results in the policy settings page and export to save it as "Sales - Gold Image". Similarly, for other groups like "Marketing" and "IT".
When you want to run the policy scan for "Sales", you need to import/restore the baseline policy "Sales - Gold Image" in the policy settings page and run the scan. You need to follow the same for other groups as well.
Hope it helps you.