you could try a dual or tri band gaming router setup centrally, or get another small business cisco router. the cisco router will provide a lot more options for controlling each individual connection to it, but the gaming router will likely provide better connections just because they are putting faster components in the gaming router. But the firmware for gaming routers leave a lot to be desired for controlling a network.
The dual band would allow for some people with newer devices to go onto the 5.0Ghz spectrum which is faster/less noisy, and older to go onto the 2.4Ghz network. Tri band would allow attempting to split the traffic on the 5.0ghz spectrum to 2 separate networks along with the 2.4 for older devices. Set it up in the main area.
Any router is going to provide DHCP service on the subnet of your choice, the gaming router is only going to do a single subnet at a time though, you'll want like a 12 hour lease time max though so you don't run out of addresses. Only a cisco small business router or maybe one flashed with ddwrt or the like would do multiple subnet DHCP service. And almost any router will have a basic firewall.