Tech Idea?

I was thinking, we can heal our units by garrisoning them or sending Monks out. What if a civ has a unique tech that allows them to heal units within a certain radius of specific buildings?

To be fair, I don't know if the way the game was made allows something like this. I was thinking that if a Castle can detect enemy units within range and if Monks can heal allied units within range, maybe there's some way to combine the two to allow this unique tech. It would certainly enhance a civ's defensive abilities, but that could be OP and really mess up the game anyways, but I thought I would throw it out there for debate