[strongSwan] client to site but as a gateway(nat)?

[peljasz]

hi fellas
a novice here, whois reading up but was hoping someone 
knowsalready and can shed some light on..

how to, if possible at all, have a client that calls out to 
a server(site) and that client would route(nat) other nodes 
on it's local lan to the site(server)?

I'd only hope that if possible that this is all down to the 
"client" as over the server I have nocontrolwhatsoever.

many thanks
L.