How to group referred nodes in views

Issue Summary

Hi,

I have been searching the drupal support pages up and down but can't seem to find the answer to my problem.

I have two content types (A = tour, B = guest). The content type B also uses a node reference between each other to allow a relationship (grouping).
B -> A
B <-> B

In views I need to create a list of A nodes with reference to the B nodes referred to the according A node.
All this is well and works fine using the following modules:
http://drupal.org/project/noderelationships
http://drupal.org/project/backreference
http://drupal.org/project/nodereferrer

Using the "Node: Nodereferrer: by field" I'm able to list the referred B nodes. But I can't figure out how to group the referred B nodes by their relationship between each other.

I found several open questions ( i.e. http://drupal.org/node/733676 ) in relation to what seems to be close to my problem. Maybe I'm just missing the right angle to this problem but I'm hoping someone has worked on a similar issue and found a practical solution to it.