Each game fork has its own rules. Additional forks may be possible if the particular game would allow it at the time. Reunifications must be legal in all affected forks.
[rab, Tuj et al] To be honest, the only reason I've got it in for this game is because I don't understand it. And suggestions are, in the grand tradition of life, there to be ignored :) And the day I am taken seriously is the day I may have to shuffle off this mortal coil. Would anyone like to explain the game for me?