What you basically need to do is edit the placeables.2da, the index in which all appearances of placeables are associated with a model. In your case you need to merge multiple 2da files so that specific placeables will be added to your module instead of overwriting/conflicting with the ones you currently have.
As said, your main problem is the 2da merging. While I am not an experienced module builder myself, I am sure that some will know of the existence of a nifty tool that will make your life easier while you are in need of 2da merging.
Edit:
2da merging is also needed for all other content that you may want to add to your PW, with the exception of tilesets and heads (if my knowledge serves me right).
Modifié par Valthrendir, 13 janvier 2014 - 05:20 .