Not sure I'm following that you only have one relationship table I would have expected multiple as generally there would be one for each item you are relating to. For myself when I have A related to B and A related to C that causes 2 relationships and I want to open B and see any A's I would use Query Builder and Tree Grid View. If your data doesn't tie that cleanly (I think it should) you can create a SQL view and create a Federated Item for the view and use that item as the source for the Query Builder. Not hard but more steps so hopefully you can use the already existing relationship records.
