Yeah only one free company can summon a primal at a time. That would not stop other free companies from having the item allowing a summon in their possession. It would be pretty sweetif you're partying out in coertheas and suddenly the sky is in flames, then snow, then downpour of rain, high wind, ground shakes, lighting streaks, flowers start blooming everywhere(moogle). You'd know that instant that a free company was fighting Odin and all the primals were walking the land. Only word I can think of is Epic...