Include children from distant parent relationship in menu

I use taxonomy_menu and distant parent so that I can define a chunk of entries in their own taxonomy and then connect the chunk to a term in another vocabulary. taxonomy_menu does not pick up the term added by the distant parent relationship.

I have vocab a containing term aa and lots of children. I have vocab b containing term bb and some children. I made aa the distant parent of bb but bb did not appear as a child of aa in the menu.

Can taxonomy_menu be enhanced to display the children added by distant parent?