I run a dedicated server, and have set the difficulty on elite and to no avail, group markers still present

For single player you surely can. For MP which was clearly in the title you cannot. /downvote AD2001 -

This is why nothing gets fixed in this game, because people think they know how to fix it. This has been attempted on many levels. If you like to play the game singleplayer it is simple to go into game settings and remove friendly/enemy tags and be done with it, but that counts towards AI, not towards other human players.