keyclone can do this fairly easily... just type the ip and port into the command area, hit 'connect' and that's it.
-yep, than you have basic broadcasting ready.
To customize what you want you have to use some keymaps (to get the numpad2 --> k') combined with the whitelist or 'only broadcast hotstrings' (to not broadcast every key), as far as I know.

Another question I simply don't know:
- Is it possible in keyclone to simply broadcast to the 'ActiveWindow' (FocusWin), without specifying it? (- I thought you need to 'add' windows to keyclone (especialy when you want to use keymaps), but as I never used keyclone on more than one pc I simply don't know).