Exactly, it's pretty intriguing when you think about it.
You can't "combine" sharingans. Only reason Sasuke got EMS is because he plugged in Itachi's eyes in Sasuke's sockets, hence you can "combine" 2 sharingans and you get Ems.
If sasuke would pluck out Itachi's eyes and put Indra's, he would most likely just have Indra's MS and thats it, since Indra was not blood relative.
Or maybe he will get an EMS or something but that means he will lose Itachi/Sasuke combo EMS in order to put in Indra's eyes.
So, in short, NO!
Its either itachi's eyes in Sasuke's sockets or Indra's in sasuke's sockets, you cant put 2 eyes(Indra + Itachi) in 1 sasuke's socket and get this super uber mega dojutu.