All you have to do is cut and paste a part and its drawing on the desk and then renaming them, of course using Solidworks. By renaming the part you will see which drawing it is linked with and in case there are both you will delete the wrong one.
All you have to do is make a composition to take away by checking the box include drawings
to rename the pieces and that's it.
Otherwise, when opening the second room, when you ask to create a drawing, you have to answer "no" to the question "A drawing already exists blah blah blah.... "
Another idea: in each drawing, make file/look for references. This will tell you which files are called.
To correct, sylvain.carvalho's solution seems to me the simplest (in this case...)
Important thing: SW does not manage paths so if your 2 parts have the same name when you load the 2nd drawing, SW will use the part that is already in memory.
Uh, guys, there's a function made for that, directly at the opening of a drawing. In the file opening interface there is the "references" button that allows you to change the assignment of a piece to a plan.
You have to select the drawing, then click on reference and point to the right file. 2s to break everything for the manipulation.