Is it customary for the wedding party to buy a joint gift for the bride?

We're already buying her an individual wedding gift AND wedding shower gift. is it customary for the bridal party to buy the bride a joint gift in addition to this?

No. If each member of the bridal party already bought a gift for her, there is no need to purchase a gift jointly.

Usually, the thing that is organized/paid for jointly are bachelor/bachelorette parties or bridal showers.

I'v never heard of that but it's a nice idea if everyone wants to do that and can afford to buy 2 gifts. Or maybe everyone pitch in and buy her one really nice thing?

No that is not necessary at all. If you've already bought two gifts... that's more than enough. That's two more gifts than I'm expecting from any member of my bridal party!

My wedding party gave me enough just being there and helping plan/decorate/clean up I wouldn't have thought to expect more. You are doing more than your share(s).

No. You did enough already.

Only if you all choose to.

No, that's silly.