|You have three different subnets. That is a problem. This makes it impossible to have one lan subnet given you want to use these static ips on the pcs/servers. It would require a router between subnets which requires nat which defeats the static ips.|
You can't use all of those static ips.
You can't use all three connections. You can only use two.
For a router to route you have to have two different subnets, one on the wan and one on the lan. Given you want to use the statics you can't have two subnets. This means you can't nat.
Only solution is to drop using the statics to one except on one line where you would have 7.
I don't see your ww-drt [which usually is done to support WDS] router doing what a real dual port router does which is load balance/failover for the links.
Dsl1 has one static ip to assign to the router1 wan interface1
Dsl2 has 7 static ips
You drop Dsl3 unless ww-drt supports wan link balancing/failover.
You set Dsl1 router to provide dhcp ip to the lan with only a single gateway.
Dsl2 goes to your "dmz" for the servers using a switch [you can use one of the routers as a switch].
Now the problem becomes you have two networks, pc net and server net that can't communicate.
What you can do is enable rdp on the server(s). Change their listening port
server1 rdp listening 3389
server2 rdd listening 3390
You would enable port forwarding on the dsl3 router so
router2 forwards port 3389 to server1
router2 forwards port 3390 to server2
This would allow you to remotely admin the servers via rdp via the internet.
Otherwise you are back at the switch only and all three subnets can not communicate. You would do manual ip assignments.