I just did CTRL on KBD#1, ALT on KBD#2, and DEL on KBD#3. CTRL-C, CTRL-V worked. I think other key combos should work too. I just tried Sticky Keys and it worked. I turned on Sticky Keys, hit CTRL on KBD#1, ALT on KBD#2, and DEL on KBD#3 and the options came up.