Use a Xantech Rp41AV. This will allow you to select vieo inputs via IR. If you want to do it Via RS232 use the IRRS232 Xantech module. You can run 4 cameras all available on demand. You can also run three cameras into a sequential switch and then run each camera into the input of the RP41AV and then run the output of the sequential switch into the fourth RP41AV input. Then you can split the output of the RP41AV and send it to the touchpanel providing the touchpanel can display a video image. Good luck
