Anyone know how I would be able to selectively pass particular destination traffic (resolved) to a particular router/server?

In other words, if any IP wants to contact for example "facebook.com" I want them to go to a different router than the default gateway. This would be outgoing only.

/ip proxy access add dst-host=:facebook action=deny redirect
-to=www.mikrotik.com comment="Redirect facebook"

Or example if someone wants to send to a particular mail server out.mailserver.com I want to route them to a different router than our main feed (to another network).

This helps if we have a connection to another ISP that allows open relay from our particular IP we can forward traffic to that ISP for those email addresses.

/ip firewall nat add chain=dstnat action=dst-nat to-addresses=196.30.31.207 to-ports=25 
     protocol=tcp src-address=192.168.1.0/24 dst-port=25 comment"Redirect SMTP to smtp.iburst.co.za"

I don't think this would work. I need 3 components here really. I need to intercept all traffic 0.0.0.0/0 on ether1 with a destination of mail.myserver.com and route it to router B (example 10.10.10.1) How would i accomplish that?

Also I haven't used a web proxy with mikrotik yet. I know there is functionality built in but obviously on a routerboard without a hard drive this would be useless. I'd have to redirect it to a real web proxy for that to work right?

I don't think this would work. I need 3 components here really. I need to intercept all traffic 0.0.0.0/0 on ether1 with a destination of mail.myserver.com and route it to router B (example 10.10.10.1) How would i accomplish that?

/ip firewall mangle add chain=prerouting src-address=0.0.0.0/0 dst-address=x.x.x.x dst-port=25 protocol=tcp action=mark-routing new-routing-mark="gatewayB"
/ip route add dst-address=0.0.0.0/0 gateway=10.10.10.1 routing-mark="gatewayB"

x.x.x.x being the IP address of the mail server
Any traffic you wanted to sent to gatewayB now, you just mark.

Hope that helps

Jimbo

Also I haven't used a web proxy with mikrotik yet. I know there is functionality built in but obviously on a routerboard without a hard drive this would be useless. I'd have to redirect it to a real web proxy for that to work right?

Don't confuse proxy with cache. You can still use a proxy without caching anything.

One more thing, although I think I saw some docs and examples on how to do this.

lets say I have a specific subnet inside the LAN that I want to route to a gatewayB as well.

Would the route be something like

/ip route add dst-address=200.200.200.0/25 gateway=10.10.10.1 <gatewayB
/ip route add dst-address=0.0.0.0/0 gateway=10.10.10.2 <gatewayA (default)

Assuming 10.10.10.2 actually is the default gateway for all traffic except the 200.200.200.0/25 traffic. In other words I just want a specific public range to get routed to a secondary gateway as well. would that be correct up there?