HTC Vive Tracker Index Issue

Hello, a newbie and a noob to VR Programming.
Im using two trackers on my unity project which i have set the device index to 3 and 4. However whenever I unpair one tracker and then pair a controller and unpair that controller to pair tracker, the tracker device index isnt 3 or 4. Is there anyway I can override SteamVr Indexing for the tracked objects or at least get the index of the paired controller and assign it? I have also tried the SetDeviceIndex(int index) it doesnt work like that neither