DC Comics had an annual Justice League of America - Justice Society of America crossover for twenty years. The context of the crossovers was the multiverse which was fused into a single universe by the 50th year anniversary Crisis On Infinite Earths. The Crisis should have initiated fifty years of new stories. Instead it started another twenty or so years of Company-wide crossovers. If something works, repeat it till it stops working.
Company-wide crossovers are parodied in the opening pages of Garth Ennis' Herogasm. The heroes of the Boys universe claim to be fighting aliens in space in a sequel to the Chaocrisis while really they are having an organised orgy on an island in the Pacific.
Herogasm is the best of the three Boys miniseries. We see the characters interacting and learn important background details. Herogasm is easy to obtain as it is Vol 5 in the Boys collected series.