Looking up the G200eW, which seems to be a Matrox G200 type of card, the card only has 8 MB of RAM and is extensible to 16 MB of RAM. This seems on the rather low end and will surely make your computer use RAM instead to do the virtual machines.
But that's not the sole problem with the card, if you look at Windows 7's hardware requirements you'll note that at least a DirectX 9 card is required. The Matrox G200 cards date back from 1998 so they at best has only DirectX 5. So yeah, this card is surely going to have a lot of trouble keeping up with the virtualized server business of the current day...
As you suggested yourself down the comments, it's best to look for something like a 1 GB card. You can safely assign 250MB of video memory to the three virtual machines and be left with another 250MB for the host operating system. And if you don't look for the cheapest card the core speed should be sufficient enough as well, it won't use the core the whole way anyway as you don't plan to run any heavy graphical stuff on it but rather use it as a server.
And when in doubt, buy something you can use for at least the next four years; it's a nice golden rule.