Assign computers in wide group to specific test WSUS group without changing OU structure

When using WSUS, I've set up multiple GPOs according to the OU structure:

• Computers
• - Laptops
• - Servers
• - Desktops
• - VM

All goes well, but I want to have a WSUS group "TEST" for obvious reasons. Without touching the OU structure, could I assign some computers from this structure in a separate group?