There are multiple ways, I think the easiest would be to create an RF profile with Rx SOP threshold set to High high for 5GHz and 2.4 Ghz and apply to WLAN.
This way frames received by AP at -76dBm at 5Ghz and -79dBm at 2.4 Ghz (or lower) would not be entertained by the AP.
you can play around with this and make it medium or low as well based on your RF requirements.
**rate helpful posts**
-hope this helps-
