Yes you can do it.
1. Use one PC
2. Get a 4 output Video card
3. Set a screen which is the total desktop size (4x4 in pixels)
4. Set 4 screen division (or more), each screen division will occupy one screen
The only limitation is that a single screen division can not be larger than 2880 pixels in width.
Always glad to help,
Sean - MediaSignage.com