Before I did the connections between Pokemon to Madoka Magica, Pupa to Samurai Flamenco, Sakura Trick to Petit Milady and Tokyo Ravens to Shakugan no Shana, I once did this connection grid between the cast of the Senki Zeshou Symphogear series, spanning two seasons.
Speaking of which, if you want a connection grid different from what I do here, you might want to check out Rabujoi’s Org Charts.