The best way to deal with shared passwords is to not have them. If you find yourself needing to share a single account with multiple users, then you're doing something wrong.
This simply is not conducive to a modern team. There are better ways to ensure security while still allowing some ease of use.
Not saying that you should store private keys in not-so-private places, but if you need to access any non-critical accounts as a team, what you propose is simply not reasonable.
Not saying that you should store private keys in not-so-private places, but if you need to access any non-critical accounts as a team, what you propose is simply not reasonable.