dhcp default route into different routing table

I have a server with 2 ADSL modems. The server does policy based routing and I do this with ip rule to divert the packets to different routing tables. I'm adding a 4G card (25Mb down, 12Mb up vs 6Mb down and 800Kb up for ADSL) now, and bridging the wwan0 interface into a vlan from a separate device. I need to use DHCP to connect on the 4G card, but I want the default route added into a different routing table. Which of the various dhcp clients is most likely to offer this sort of flexibility? I've never done any more with Linux DHCP than to just configure it and use it... Thanks James