While you may run into some limitation LastPass sounds like it may fit the bill of what you are looking for. It uses a Trust No One infrastructure so data is securely locked. You can set up groups, share along users, save password, notes, files (ie keys).
There has been a new comer recently that works much the same way as LastPass called Dashlane, but I have no experience with it and have not read the white papers for it though they are available.
Alternatively you could role your own with something like Sparkleshare, Bittorrent Sync, or rsync and store application called Keepass which uses Truecrypt to encrypt it.
I would provide links to more info but I'm still under the 10 rep minimum so I can only provide the one.