keep them away from the apples I think. I might have imagined it, but there's def one fruit that makes other fruits in its company rien faster and i think it;s apples. Sure someone will say if I'm wrong! And I'm with you-ripe bananas are gross but I love them still a bit green!
Keep them in the coolest place in your house. You can use the fridge as long as you don�t mind the skins going a funny colour (the flesh will be fine).
Alternatively, buy fewer at a time and eat them quicker!!
I believe that bananas shouldn't be stored along with other fruit, can't remember why, but if you buy an avocado pear which isn't fully ripe then place it near bananas and it will ripen more quickly. The process, I think, is something connected with enzymes, whatever they are! So you'll just have to buy another fruit dish just for your bananas. lol Caz x