ISA and two ISP

i have a microsoft ISa server as my proxy my network is 20.0.0.x and the isp is 208.176.2.x.
all client machines connect to the internet thru the ISA with firewall client. the ISP also host our mail server. Recently, the company got a new ISp intended to run inparralel with the current ISP. TH eproblem now is that i want the isa to direct mail request to the old ISp 208…. but redirect all other web request to the new ISP. In answering this question, ill like to know to know if the ISA server support more than two NIC.
if the isa can no tdo this , can a router do this? although this should be a last resort cause, there is diffrent kinds of scheduling policies set up on the ISA which the router can not do.