Is there a way to jut ‘attack’ a secondary castle instead of ’occupy’ing it?
The only time you would ever occupy the secondary castle anyway is if the durability has been reduced to 0. Unless its an NCP castle in which case you will occupy it regardless of its durability. So you can attack it all you want even if the command is occupy. You wont ever actually occupy until the durability is 0.
I think he means attack instead of occupy, in so as to raid rather than capture. (difference being that you won’t need a free slot for attacking). And no, sadly you can’t.