You could mark items in the feed to space repeat for yourself. This would also function as a “retweet”, which would align incentives such that content that gets promoted is actually durably useful or interesting. The posts people make would repeat to themselves too, so the source content should be good.
I think that this should turn some of those temporary friendships into lifelong ones instead!
So schedule a call for a week after the cruise. Then 2 weeks after that. Then 3 weeks after that. Then 5, 8, 13, 21, and so on.
Each call will bring back for both of us what it was like on that cruise, bring back that connection, and make both of us feel that any other call (say to meet on another cruise) would be welcome.
At least that's the theory. I won't know how well it would work until after I try it.
(My wife and I are doing something similar. Every week we pick a memory that we put into a system we have. The joint review of our memories each Sunday is a high point. So I'm sure from that, that this would bring back that sense of connection.)