Ipad - optional Group Set sync

I would love the ability to maintain the main masterlibrary on the macbook and then regarding space have the ability of not having to sync the whole library to the iPad but to be able to highlight and choose to sync designated group sets.

For example.  I currently have my study Module 4 in the library and have synced this to my ipad and have downloaded PDFs.  I now move onto Module 5.  I no longer need module 4 on my iPad or the downloaded PDFs, only Module 5 information.  However, I cannot remove those Module 4 PDFs on the iPad without losing them in the main library, which I don’t weant to do.  Nor do I need to see any references relating to module 4 on the Ipad.  But I do want to keep my Module 4 master information available within the main desktop in case of need.  Presently I am told the only way I can do this is to delete the whole Module 4 group set.