Test a embeded system (PC) from another PC

Question

Got a customer request but no idea can it be done. So need your opinions on this. This might be a utterly stupid thing to ask but yet need some facts so can work out best solution.

Scenario,

My Customer is an OEM Manufacturer. They make an automated system with a embedded touch screen (Windows XPe) this system got a button panel with some LED indicators (apart from keyboard) and 7 USB Ports. These button panels and USB ports are checked before sending to QC process. Currently a USB thumb drive with standalone executable with all indicators and controls flags is inserted to one of the USBs and then will run the exe. This exe capture user inputs from button panel and indicate which button is pressed so that it can be verify as working. And from program user can set LED indicators to different states (flashing, steady and off) so they can be verified as well. Once this is done then USB thumb drive will be inserted to each port and will verify it recognise. But after each verify step it needs to safely remove the drive from task bar. Once each test is finish user required to fill up the sheet with all pass and fail states for the entire button panel, indicators and USB ports. This is a quite length process when its come to mass production.

Apart from this embedded system all other components which suppose to connect to one of above embedded systems are tested via a program which I make and records all test outputs as they are tested. This program installed and components are connected to a testing embedded system.

Requirement,

What customer asks, can my program test completed embedded system with our host system (testing embedded system, may be via USB to USB) Its more like Testing a PC from another PC. Any ideas ?

Additional Info. Apart from USBs there is one Network Port.

Thanks for looking, Feel Free to ask any questions. Any opinion is appreciated.