All together in the whole game. But, really, trying to simplify the relics rule was an error and you better stick to the Incan Gold rule (which is the same, except that one relic is added to the deck when entereing every cave, instead of all at once at the beginning)
Maybe I've been playing wrong as well. The 2016 Diamant UK rules seem to indicate you only vote on Relic cards. Should the group be voting on every cave card that comes out?