Hi Team,
Is there a quick way of combining multiple different PCB designs / projects in one ?
Idea is to order one common stencil for all PCB’s. This is only for prototyping purposes.
Sounds frugal, i admit !!! 
Cheers
There are a bunch of solutions to panelize gerbers. Some are provided here:
Depending on your manufacturer, you may also be able to ask them to do it for you.