Thank you Magica Alfa! I have 4 keyboards and a pedal board so there are plenty of connections. Anyway I finally found the very simple freeware I needed in http://www.musiclab.com/downloads/free/ (Midi Connection Center) It allows me to connect up to 4 input drivers to 4 output drivers at the same time even syncing the tempos so now I play the Psr styles playing the Korg's drums and adding the Real guitars pads to them. With one keyboard I play the right hand sounds of the two arrangers and the workstation. I don´t need to change programs using midi because all my keyboards are set up in a way that the buttons of all of them are at hand. I thought this kind of softwares were very common but I see not many here know about them may be beacause it's a little bit crazy to play so many keyboards live with a computer at the side. Check a picture of the keyboards at: http://www.frappr.com/?a=viewphoto&id=5492656&pid=10585066

[This message has been edited by vagro (edited 01-10-2009).]