Are there differend 'sprites' in the 'humans' family ? And therefor you can't pick the nearest by its 'instance name' (instead of using the family name as you do now) ?
Anyway. Its a bit of a dirty trick anywayz. I wanted to show you how to go for a 'distance map' solution.
But, if youre humans family contains differend sprites (not just a family of one sprite) then i have to retink this. Probaly need two familes.
The nearest family member (or instance) to the postition of a member (or instance) is that member on that position. Got to work arround something that is in base totaly logic. And its not that much work.