How do I prevent my Mac from switching Wifi connections when at home?

I have a MacBook Pro, running Mac 10.9.5. I connect wirelessly to the Internet through my home Cisco LinkSys E900 router, which sits just 10 feet away from my computer. However, frequently when I leave my computer inactive for a period of time and then return after waking it from hibernation, my Internet is connect to an xfiniti Wifi hotspot, without my having done anything. How do I configure my Mac so that it will ignore the xfiniti Wifi hot spot and remain connected to my home network?