Grocery Co-Ops / Buying Groups

Over the last few months or so, my wife has been part of a group that gets together every couple of weeks and does meal prep. Usually it's anywhere between 3-6 ladies, one of them will make a menu for for say maybe 4 dinners and stuff to make lunch for a few days. One person will go buy everything, and then they all equally split the cost. On a Sunday, all the ladies will get together for a few hours at someone's house and the will prepare all the meals for cooking later in the week. My wife leaves with a box full of tupperware containers and pans and zip lock bags of food cut up and prepared and ready to cook.

This seems to work out well as it's pretty cheap (since there is little wasted ingredients since they all share stuff like a bottle of something when you only need a cup of it). Also it helps to come home from work and just throw a pre-ready pan in the oven or whatever.

Anyways they are thinking of somewhat taking this to the next level and doing buying group. Basically they would come up with a list of stuff every 2-3 weeks and go buy everything in bulk at sams, costco, restaurant depot, etc, and then splitting everything up. The idea that, for example, a four pack of ketchup at Sams is super cheap but it would take a while for one family to use it up, but four families would do it quicker. Could take large cuts of meat and cut them up ourselves, etc. Could also use this for dry goods, toilet paper, etc .

Anyone part of anything like this? Any apps out there that might facilitate this? Handling payment, tracking stuff, etc.