It would be really beneficial to have groups of users that you can share passwords too, rather than on an individual basis.
For example: Groups, Level 1-4
User A is in Level 1
User B is in Level 1 & 2
User C is in Level 1-4
A password shared to Level 1, user A, B and C would gain access as they all have access to level 1 password.
A password is shared to Level 4, user C would only gain access as they are the only user who has level 4 access.
A sharing model with groups of users makes it a lot easier to share password data. Having to go in for each password, set the access and then copy that across to others on a one-by-one basis is very time consuming and an administrators nightmare.
If you had a new user, you can slot them into the groups in which they can access and then all the rest is automatic, you won't need to manually share any passwords at all.