In fact, this is perhaps an idea for a future section of this forum: anyone planning a trip where he/she/it would like to have other cars joining (perhaps open to other 4X4) or would accept taking some passengers could announce it on such a new section.
@Stu_Barnes ... what do you think?
Could be by continent, or in some cases by country if there are too much proposals.
But perhaps this exists on other platforms. I never searched for it, because I am mainly a "lonely" traveler, but that doesn't mean I would not be open to it.
I pick up hitch-hikers when I can, although this is an almost extinct species, at least in Europe. I hitch-hiked myself a lot when I was younger.