Being in Tower and all (and this applies for a few other clans as well) I sometimes find myself working with the opposite alignment.
Now, by common logic, since we're in a common cause...and in addition, since it actually says in our large tome thing that loyalty to the Tower comes before loyalty to alignment, we should work together.
We do, of course, but we can't actually group directly.
I remember that in Kiri's Solace, this wasn't so, and I was wondering if such a thing could be applied here...that a clan would override alignment grouping restrictions.
Even if we're different alignments, we're working together as companions, as it were, so it would make sense if it were so