I want to make a pvp map which has 2 spawnpoints on the map. The spawnpoints are closed off with an iron door. The teams can both get ready by flipping a lever. Now i want to make it so when both teams are ready the doors open. This could be achieved by a memory cell. I know because i have made these before but i cant remember how to build this and i also knew it wouldn't work if i added more doors. Any suggestions?