Quick Question about SL Server

Yes i know i should upgrade but i am holding back for compatibility reasons , One question though that has been a bit on my mind is about the capability of mac os X server SL to support multiple gateways , i have been having headaches regarding this particular issue , let me explain. I have 2 interface leading to the outside world one of the a very fast interface coming from a relatively reliable provider and a slow interface coming from a sluggish but very available provider. My users connect to the local DHCP server hosted on my mac os X server Snow leopard machine and i would like to serve them on network with whatever would be available reliably. Is there a way to designate multiple gateways through nat to serve the DHCP how could this be relatively configurable ? Thanking you for your time and attention and waiting to read from you soon , Best Regards, Bertrand STERN PS: There aslo seems to be an article about the subject on this site under story number 20090830224048913 but unfortunately it is no longer available.