This screen can be used to view all the documents belonging to a Document Group and to look up which group a specific document belongs to. This screen is found in Administration > Company Details Menu > Document Distribution Groups.
Use the Find option to search on a Distribution Group

Then search for the document in the Document Name list.

The screen will advise the Distribution Group the document belongs to.
The same screen is accessible from the Personnel Screen by double clicking on a Document Group in the Document Distribution Group section.