How to set up a contextual filter or child relationship? Every now and then I'm re-attempting to set up a decent taxonomy explorer/browser. I have already managed to customize a tpl file for that (oh, I know, tpl should not contain advanced logic, some day I'll learn how to do that properly). Now I decided to give it a shot using Views. While I managed to set up a view for the top-level listing, now I'm trying to set up a decent lower-level browser.
I don't think it's possible, but maybe you will prove to me that it is.
My taxonomy has a very simple structure in that at a given level it has only branches or leaves, never are they mixed. Now, at some level (the depth is variable at different branches), the branches end and the leaves are to be listed. Therefore I'd thought this logic would be appropriate:

on page taxonomy/term/%
list items which
(a) belong to vocab X
and ((b1) are either children of parent with tid=%1
(b2) or are published nodes of content type Y with term tid=%1 assigned.)


For (b1) I have defined a parent term relationship and used it as a contextual filter. This alone works, but I don't know how to set up the b2 part. Can I re-use the same part of URL for another or'ed contextual filter. The '%1' string does not seem to work when entered in the filter section. What am I doing wrong?

Thanks.
Apparently there is no way to solve it using contextual filters and relationships. I solved the b2 part by using a separate dedicated view of content nodes as a No results view. It works because the taxonomy has consistent, non-mixed level contents.