Well you can do it but only if you're playing the minor nations. Say if you play as Romania, Hungary...then you give them expeditionary force and the German will do the rest. That way you still can be able to control the other units
I personally like to play as these minor nations since managing the entire front is too much for me!
For the Croatia I think you should give your troops's control to the Romanian instead, they're the biggest AI in the East generally. The smaller AI will only trying to defense its own territories
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If I am not mistaken, if you give troops to somebody as expeditionary forces they will use that country's doctrines and technologies, so you might be shooting yourself in the foot. '
I don't think so. I did it before in both way, I was Hungary or Romania, I gave my troops for Germany as expeditionary troops and my troops still perform as poor as they're (can see clearly through the org, if they're using German's doctrine then they should be much higher) and their stat should be better.
Oh and since we have this threat I want to ask this.
In vanilla HOI2 both the receiver and the owner of the expeditionary force can't interfere with those formations (i.e they can't split the expeditionary force to smaller units). However in DH it's possible which is very annoying, say I have a corp of 12 infantry with Art and Eng, together they're a big corp and worthy, when I give them as expeditionary force the AI split them out which is very silly!
So how can I disable the ability to split expeditionary troops?