Making a custom entity icon using the API

[Lance Gable]

Hey, I am looking in to fixing my custom entities not showing up in JourneyMap, and I would like to know, how can I make them so they only show up for specific users? My mod lets players build an army of skeletons, and these custom entities currently don't show up. I want them to display as the white entity marker to allied players, blue(like a tamed pet) to the owner, and not display for anyone else. Is this currently possible? If so, how? If not, would you consider making this possible?