Currently there are two options for troop recall either go a specific castles garrison tab and select the troops to recall, or recall all garrisons of certain types whether they be seige/ reinforcements. 

There are a couple of possible modifications i'd like to suggest, although I dont know how cumbersome they would be in terms of coding and slowing the game down.

1)add tick boxes to each castle in the garrison pages so that you can select a number of castles from which you can recall all troops present, without needing to select the individual troops from those castles, or having to recall troops from all garrisons of that type.

2)recall all non league/ non allied /non friended garrisons 

In addition to the accepted suggestion of reinforcing leaguemembers from the league pages, would it be possible to add an option to send x units of whatever type to all leaguemembers, provided that you have sufficient troops available to do so.

Thanks for your consideration