‘You can pass wp_query args into bb_has_topics(), but I can only only come up with code that shows topics from one forum – not multiple forums.’
I’m afraid I don’t have time at the moment to do lots of coding for others, but take a look at this plugin
http://www.rewweb.co.uk/bbp-private-groups/
Look at includes/topics.php for how I did this for private groups – called pg_has_topics, it may give you some help – I used ‘post__in’ to create a list of topics to display
So you could do a coupe of loops to create this list and the pass that to the bbp_has_topics function.
‘post__in’ is realy, useful sometimes
see