Please note that goral_ mentioned unicable. If you must connect 3 or 4 unicable LNBs, I believe that the unique solution would be to install 3/4 quatro LNBs and use one Unicable/DCSS multiswitch with 4 INs and 2 OUTs (or more if more receivers must be connected).
The problem could be to install so much LNBs on a single dish because such products are bigger than common DCSS, 1 OUT LNBs. So a specific evaluation is needed.
No idea which multiswitch could be used, but surely EMP Centauri or Spaun are good manufacturers for such products.