You need to talk about 'tuners' rather than 'cards' here.

If you can find a dual tuner card, then it should be possible to
expose 2 tuner instances on that card to WM Encoder, assuming the
motherboard can take the data transfer hit. Typically, such cards
might be found inside media center PCs so those sorts of devices are
known to work for display of one channel and recording of another.

If this is a private LAN then you could investigate WMS multicast
delivery, and let the routers on each subnet take the strain. Time to
speak to the infrastructure techies at your organisation.

In this instance, multicast would result in WMS broadcasting a singe
stream for each channel encoded by WM ENcoder, and leave it to the
network routers to setup multicast groups nearer to the users.

The overall traffic at the first hop would be the overall stram
bitrate, and that would be distrubted at each router node. If no
listeners were on a particular managed network segment, then no
multicast data would pass over that segment of the network.

Cheers - Neil
------------------------------------------------
Digital Media MVP : 2004-2007
http://mvp.support.microsoft.com/mvpfaqs