Hi,
I'm building a new house.
Having 4 cats, I'm looking for a small door which:
a. My cats can open to get in and out.
or better
b. Identifies ONLY my cats (e.g., via a magnet or similar device attached to
the collar of them) and lets ONLY my cats in & out.

If any body knows about such doors (and the collar device) I'd be happy to
get some info.

TIA