Router Mode on ASUS AC5300?

[David Muszynski]

In the past I've used multiple routers on the same physical LAN to create subnets. With the Cisco SOHO routers I've used in the past there's always been a button that is gateway/router mode. I turn the edge router to gateway mode, the other routers to router mode, setup static routes and everything is happy.
I'm trying to do the same thing now with these new routers I just picked up. As is they seem to be doing what I want them to do but NAT is turned on for both the ASUS and my edge router in order for packets to traverse the subnets. If I turn off NAT on the ASUS router packets die trying to pass subnets.
I can't seem to find a button that does what I want in the interface, if it's there can someone show me where? If not does anyone know how to achieve what I want to do with another set of instructions so I'm not dealing with double NAT?

Here's what I'm working with:

Cisco (edge device)
WAN IP (static from ISP)
LAN IP 192.168.2.1
LAN 192.168.2.0/24

ASUS 1
WAN IP 192.168.2.2
WAN Subnet 255.255.255.0
LAN IP 192.168.3.1
LAN Subnet 255.255.255.0

ASUS 2
WAN IP 192.168.2.3
WAN Subnet 255.255.255.0
LAN IP 192.168.4.1
LAN Subnet 255.255.255.0

I have routing statements set up on all devices to send traffic requests to the correct subnets.
Like I said, everything seems to be working as is, but I'd like to make it as bulletproof as I can.