Filtering scanned MAC address and display in text / list box

Question

I am working on a tool that connected to my Bluetooth receiver and scan and get MAC address of BLE devices. So far I can scan and have the mac address continuously display in textbox. I am having problem with filtering MAC address?(Our assigned MAC address 88 99 66 55 4X XX the last 12 bit is free to use). How can I filter this while scanning and put it in Listbox or Textbox for later use