Alienware 15R2 Multiple Monitors Graphics Adaptor Resolution Problem

Hello Dell Community.

I have recently tried to connect my Alienware 15R2 Laptop to a television screen (not a specialised pc monitor) to use as a second screen. I initially had some problems getting the resolution right (it cut off the corners of the screen) but have since made it mostly fine by uding a custom resolution which keeps the majority of the screen.

The problem occurs when I try to play games on the second monitor, the games do not have the option for me to play at the custom resolution I am using (1700x900) and if I try to use fullscreen I cannot see the whole game screen. 

I was looking through my graphics properties for my display adaptors (An Nvidia GeForce GTX 970M and an Intel HD Graphics 530) and it seems that my Nvidia card can only detect my additional monitor whereas my Intel one can only detect my actual laptop one, this means that I cannot really change the options on both monitors together or change how they interact etc.

Any help on how to control which adaptor controls which screen or anything else is very much appreciated.

Thanks in advance.