Replicating Windows Critical Updates To Many Same Model PCs

I have an industrial customer that would like us to manage their Windows and SCADA system service packs and updates. They have 15 PCs that we will need to have synchronized updates installed between them and only updates that the SCADA system software developer has approved. Once an offline PC has been selectively updated it must be tested for proper functionality in a test environment before rolling out updates to the 15 PCs on the production floor. Each of the 15PCs will have unique settings and software installed but all will have the same Windows SPs and updates installed.

In the test environment I have internet access to manually request for Windows updates. I then select only the updates in the critical list that is on the approved SCADA system list. Updates are installed and a day’s worth off testing is conducted to confirm all critical updates have not created any system performance issues.

Production PCs are on a private IP segment with no possible chance of getting temporary internet access approved. Is there a way of replicating the selected windows critical updates completed in the test environment and sneaker netting them to the production floor PCs? I would imagine the updates would need to take place in the same order as windows automatically took care of in the test environment.

Thx, I will look into both options further. :)