VPN controlling access

I have just got a R7000 router and i am wanting to use the openVPN on it.

My main worry is security as it just seems to generate one set of files with no user name or password support for each user.

I was wondering, if I use  "Configuring Access Control on Nighthawk Wi-Fi Router" to allow only known MAC addresses to access my network, would that also be true when using the VPN, such that if the MAC address was not in the "access control table" it would'nt allow VPN access even although the user had the files.

Its just that if anyone ever got access to the files i would have to turn off the VPN feature as they are same files. So I'm hoping that this will be a possible solution to my dilema, using "Access control" features.

Hope it makes sense and someone has come across this problem before.