pre-Christmas virtual PostCrossing MeetUp (Finland)

I’m so puzzled at how the Finnish PostCrossing group can produce postcards for the virtual meetup that have signatures, stamps, and icons on the back?! Usually at a meetup — at least those I’ve attended in the US - we have a pre-printed postcard with a blank back. We then spend lots of time (it’s quite tedious, which is why I don’t go anymore) signing or stamping the dozens (hundreds?) of postcards that the members have bought. Some people will buy 100 postcards and want each one to be stamped/signed by each of the attendees. I know these are hot collector’s items for the senders and receivers, but my hand cramps and I get tired doing the same thing over and over.

Maybe if I could figure out how the Finnish PostCrossers do it, I would be more inclined to go!