2 Internet Connections + 2 NIC Ports

[Zico]

I'm looking at joining vFast (www.vFast.co.uk) as a complementary internet connection at home.

Our 2mb DSL connection with Sky is fine though, when everyone at home is online, doesn’t hold up very well with multiple simultaneous streaming/surfing or downloads (note one brother streaming live football, dad surfing, two other brothers surfing/gaming or streaming and me surfing/downloading + Xbox Live).

Now to my question.

If I were to have a Wimax connection via a broadband router connected to one of my motherboard's gigabit lan ports and our Sky DSL connection via the Sky router connected to the other gigabit lan port, can I tell Windows to use one connection over the other without having to disable/disconnect one of the cables?

If I have to disable/disconnect a cable then I would loose connection to our home network (which although a minor inconvenience, would mean that nobody could print or transfer files from my own PC during that time).