Need help with irule to SNAT only server initiated traffic, but don't SNAT clients traffic

Want to SNAT internally originated traffic going to specific URLs, all other traffic are not to be SNAT'ed. i.e All clients requests, do not SNAT, but servers initiated traffic to for instance, , and should be SNAT'ed through default gateway interface.

The SNAT will use the same pool (client_pool) but not same VS.

The clients traffic VS = 10.2.2.2 (VLAN 2)

default gateway 10.2.5.1 (Vlan 5) interface 2.2

Should I use switch or string match without impacting clients request?

For instance, when HTTP_REQUEST { switch -glob [HTTP::uri] { "/" { Exact match for / HTTP::redirect "; } "/custom" { URI starts with /custom HTTP::redirect "HTTP::uri" } "abc1.com" - "cabd1.com" - "utss1.com" - pool client_pool }