network cards

I have a network card (internal), a wireless nic and firewire.

I use the internal card for home networking 192.168.x.x and internet
connection sharing (ICS) with this computer as the gateway to the net.

The wireless card is for work and on 146.x.x.x.

I have found that in order to get ICS working at home the firewire and
internal card must be on a bridge but then I cannot connect to the wireless
lan at work. The only way I seem to be able to connect at work is by
removing the bridge.

Any suggestions would be greatly appreciated.

Sue