You can just put these of buildings as a OOB object in the unplayable area of your map, probably i guess since they are very tall and big and bugged...*shugs*
But as far as i know you cant enter any of the top floors or destroy them (unless v1 or howitzer
) , since each building block ( i think i had over 50 of those ) acts as a shot blocker so it would take an awful long time to turn it into rubble.
PS. Isn't there a blocker object that prevents buildings from being garrisoned?