Challenge favorite decks within coalitions

Sorry if this is a repost, I couldn't find anything with the search. It would be nice if we could challenge the favorite decks from anyone in a coalition. The training grounds are nice for general testing but not if you want to do something specific and this would also be a nice way to play against friends without actually doing real-time combat. In addition it might entice people to join an active coalition who otherwise would be playing solo.