I thought you might be interested in looking at Marker, local to one side only..
https://forums.bohemia.net/forums/topic/81869-marker-local-to-one-side-only/?do=findComment&comment=1400244
× Pasted as rich text. Restore formatting
Only 75 emoji are allowed.
× Your link has been automatically embedded. Display as a link instead
× Your previous content has been restored. Clear editor
× You cannot paste images directly. Upload or insert images from URL.