Coinos has a "Create a fund" feature that could be used for that kind of use case. Multiple people can contribute funds and you can limit who is able to withdraw the funds and the history is visible to everyone with the link.
Discussion
We've also had success offering bounties to people who refer us to new merchants to onboard: https://coinos.io/bounties
I am confused, there is "nostr connect" on coinOS, but when I click it, it opens in amber, I hit approve and nothing happens when it sends me back to the PWA.
Hmm, it works for me. Amber is supposed to sign an auth event we provide which then should sign you into a Coinos account associated to your nostr pubkey or create one if it doesn't exist.
What browser are you using for the pwa cuz I tried brave and iron fox and after amber signs the events it just goes back to the qr code page and nothing happens