New'T'ech
Recruit

[Used Google translate]
When a player is in an army, when clicking on the squad icon (lower right corner of the interface), a small menu appears with the item "transfer troops" included.
So, you could do this: if the selected squad (from above) is the squad of your companion (with which you can freely exchange troops and prisoners), then when you select the "transfer troops" item, the mentioned interface would open, and not just "transfer troops" interface.
When a player is in an army, when clicking on the squad icon (lower right corner of the interface), a small menu appears with the item "transfer troops" included.
So, you could do this: if the selected squad (from above) is the squad of your companion (with which you can freely exchange troops and prisoners), then when you select the "transfer troops" item, the mentioned interface would open, and not just "transfer troops" interface.