1 Keyboard/Pointer, Many X Servers?

[Hibiki Kanzaki]

For synergy or x2x, do I need to put something in xorg.conf
saying not to try to use /dev/input/mice or whatever?  There
will be several X processes running on the same machine,
but only one (or none) of them would actually have the input
events coming directly from the keyboard/mouse... I need to
make sure the other X servers do not try to use them.