BuckeyeFan85

Hello, this is my first post on here so sorry if this is in the wrong area. I am planning on buying (3) sets of the AW-650 speakers (so 6 total speakers) to go around my pool and fire pit areas. I have a 20x40 pool and the fire pit area which is about 20 ft from the pool. I am planning on putting one on each of the four corners of the pool and one on each side in the middle. I am trying to find what the best amp/receiver would be to power all of these? It would be great if there was one where I could choose if I wanted to output to all six at once or just pick two or three to output to at certain times. also, is it okay if these are mounted outside and not under an overhang? I live in Virginia and the summers get in 110 degree days and the winters get down to the low teens with occasional snow. I would want to leave them mounted outside year round. Thanks so much for any advice.