I have built a beacon receiver that operates a relay anytime a beacon (with our major code) is present. The idea is to lock a door anytime a beacon is within 10 feet of a door. I see that your beacons have a tx power adjustment. Can they be adjusted down to that level?
You can try tuning them all the way down to the minimal -30 dBm broadcasting power. It’s hard to say what range that’ll give you—it depends on the sensitivity of your receiver, line of sight, etc. You can always add an additional requirement that the signal strength (RSSI) with which your receiver detects a beacon needs to be above a certain level, thus ensuring that the beacon is close enough.