I'm not an expert and i haven't tried this, but i would think you could use the pass tool and encrypt the files to multiple gpg keys, and share those files usin

I'm not an expert and i haven't tried this, but i would think you could use the pass tool and encrypt the files to multiple gpg keys, and share those files using a git server which you control. That sounds like a rather easy homebrew password manager that supports shared logins, i would think. Disclosure: happy user of pass, but haven't tried encrypting to multiple identities.