In a game with Max AI players(10)

If I am in an Alliance with another empire(2 empires in total) say Alliance A and I want to join with another alliance which has two empires say Alliance B , I am unable to do so. This breaks the game as other empires form an alliance with 4 empires but Alliance A & B will forever be stuck with 2 empires each unless someone leaves the alliance first. The AI will never leave the alliance unless the player breaks the alliance. This makes it hard to rejoin an alliance at times as the alliance you break, that AI becomes wary of you and does not want to rejoin the new alliance. This seems ridiculous.