hi
AFAIK i dont think you will be able to use WCCP for particular webpage/servers.
Better aggregate all traffic onto a L3 Switch wherein you can apply a policy specifying that the traffic destined to the intended servers to go via the proxy ( which you can setup as default gatway).
You can do the destination address matching using Access-lists matching the remote server ip address.
for the rest of the traffic it can make use of the normal routing in the L3 switch which could be your router to go out to the outside world.
regds