If I send legendary troops to the fortress unaccompanied, will they bind with excess appropriate troops I have already sent to the fortress? Or is it only the accompanied appropriate troops that travel with the legendary.

If the answer is the latter I'll need to bring all my troops back from the fortres and repair them and send them back.

That just doesn't make sense to me.

Likewise if I send just troops (no legendary/s) to the fortress and I have excess legendaries of the right type at the fortress will they bind?