mobile

Does anyone know if it's possible (maybe an XPOSED module) to lock the phone so that if it's connected to a WiFi network it disabled mobile data? For some reason, my phone was still using mobile data even though the WiFi showed connected. I think it's because my work network requires you to log on to a webpage after connecting and apps may have had trouble connecting so they switched to 4G. I watched a few YouTube videos like that and burned through nearly 1GB of my data which really stings. As a result, I've taken to manually disabling mobile data when I connect to WiFi.

I'm running LolliGPE, S-OFF, etc.