We have an interesting way to get around this in the SCA. We use peerages (Royalty, Chivalry, Pelicans and Laurels) and fealty. The people who hold the peerages are without exception experienced players who are skilled at whatever specialist area they are in. They take on newer members in student/teacher roles (knight/squire, laurel/apprentice, Queen/lady in waiting etc).
It has a lot of benefits, including the obligation for the experienced players to pass on knowledge, the sharing of the usually greater resources of the experienced player (armour, costume, research books etc) and a feudal hierarchy.
So, while you have cliques of players based on when they started, you also get households of players in the opposite direction where you may have 1-2 very experienced players and 3-4 people who joined a few years back and some complete beginners.
The culture is such that there is usually some small amount of pride in being in a good household.