share the fare - journeys throughout Europe
(Mitfahrgelegenheiten der Mitfahrzentrale-europaweit mitfahren von A-Z-Mitfahrzentrale.de)
For those who don't "munch" the German language, it is a "share the fare" system of journeys throughout Europe.
I did, decades ago, and it went quite well.
It would be interesting to have some feedback if you have tried it.