I think I know what you mean. I share the identity relation with my aunt, my foster mother and a guy I used to chat and talk over the phone with for a period of time.
Although we are vastly different in many ways, where intention and perception are concerned, I got a pretty good read on them.
Conversly, I have learned much about myself in observing my type identical...Can be a little painful if you're not ready to learn and work to improve yourself.
Just imagine two ISTJ's getting into each other's POLR! Not a pretty picture.
I have a 15 year old cousin who tested as ENTP...he already has that crafty look in his eyes!