This is one of those areas where having a naming convention is very helpful. You can limited the vertex groups that you see by clicking the expand arrow at the bottom of the vertex group list. This will show the search box and 3 icons(The double arrows hides vertex groups that match the search. AZ organizes the groups in alphabetical order. The arrow is used to reverse the order) Then in the search box type a few letters or name of the vertex group(s) you want listed. For example if you type T and you have 3 groups named MyTest, Test, and Group. then Group would be the only one not shown. If you click the double arrows then Group would be the only one to show. Hope this helps.
