Mark a token as visible to players regardless of line-of-sight, light, or fog of war?

I make use of dynamic lighting and fog of war on lots of my dungeon maps, but my players sometimes go down separate hallways and lose track of where each other are. I'd like to find a way to let them see one another's tokens to know relative position, without actually seeing more of the actual map than what their current token should be able to see. Is there a way to do this, perhaps with an API script? To make sure I'm being clear, here's a sort of example or mockup of what I'm asking for: Hex0r can still see the drone on the other side of the building, despite line of sight being blocked and having no "light" on the drone's hex.

I think there's an out of the box solution using the Carry Tokens script, available on the One Click install. The script allows one token to "carry" another token with it, above or below in the stacking order. An invisible  token " light crumb " could be set to be carried by the drone in the example above. It would have minimal light and vision, just enough to illuminate and see the drone's position.