You can merge the objects by merging the script code (copy&paste) in one object or by CALLing each sub-object out of a new main object.
I would prefer the second method, because you don't have to care about the environment of the other objects like double used variable names or done transformings of the coordinate system.
You can do all ADD/ROT/MULs necessary in GDL to bring the origin for your existing object in the right position in space. Then make the CALL with all the settings (e.g. a=2, visible=2 etc.) after "PARAMETERS" you would do, if you place the (macro)object in the floor plan.
As you have obvisiously done you can use the "save as object" option the automatically produce the main object. In this case you have to edit the resulting code to return it to be parametric (if necessary).
You can do the CALLs as often as you like. You can insert it into loops too:
for x =0 to 20 step 5
addx x
CALL "Raamja_dalja" PARAMETERS ......<- your settings
del 1
next x