Limiting Service that pass through F5

Hi,

I have a question about creating VS service traffic separation.

so, i have 2 server and i install an application that runs multiple service on those server ( like http, https, and smpt ), and i want to do the load balance.

the problem is that i want all users access http and https through F5, but if they need smpt service they will not through F5.

Here is the illustration for it :

you can see the topology above, let me explain it,

i have a firewall, it carry the NAT service, that translate the virtual server ip to ip public, and then there's F5 that translate the Virtual Server IP to the Server's real private IP,

So, let me clear it, the traffic from public is :

User - Firewall ( 1.1.1.1 to 10.10.10.10.) - F5 (10.10.10.10 to 192.168.1.1 ) - Server (192.168.1.1)

Is there any command in iRule that can make it happen?

(NB : user access the server via domain, so address 1.1.1.1 to example.com)