when using DesignBuilder i made a mistake by building two builldings instead of two blocs , i have one buillding contain 2 floors R1 and R2 but the mistake was that i build R1 as a buillding not floor (bloc) and R2 as well as a buillding in the top of it , is there any method to fusion those 2 builldings in 1 building whith 2 blocs ??