Multi-user Contact Manager, Any Ideas??

I'm in the process of recreating a contact manager for a group of salespeople at an office I work for... What I want to do is be able to consolidate all of the contacts in a single contact database on the back end. Then the records will have specific users specified to each record, and what I want to happen is that the users will open up their own database, and they will only see the records pertaining to them, and they can't change who gets the records.

Here's where it starts getting tricky. I want the manager to have access to all of the records, and I want him to select which user's contact list he wants, and it brings up those contacts. I want him to have a combo list on the screen where he can select who gets which contacts, and he can change them throughout the different users.

Related to each of these contacts is a subform, called CALLS... When this button is clicked, any information regarding past calls is brought up, and the user can add information about a call that is made. This checks the previous form that is open to find out the ContactID so that it can open up the corresponding CALLS entries in the CALLS table.

Here's what I did: I created a new contacts form for each salesperson (there are 5 salespeople). Then I had to create a new subform for each salesperson for the CALLS, and then the information will be gathered from the proper subform to the users contact form.

I can do all of the above, but it seems kind of redundant to do this for all of the users, and I'm wondering if there is an easier way to do this. Also, in the future if more salespeople are added and I'm not here for the company to set up the new users, I would like to see if there is an easy way for them to set it up (like adding a new value to a few different spots)...

BTW: One difficulty is that they are already using a previous contact manager (not designed by me) that has hundreds of contacts, but each user has their own separate copy of the contact manager which is just copied and pasted onto their local drive when a new salesperson arrives. I will also need to import all of their previous contacts, and I would like to maintain as much of the original structure as possible to avoid dealing with user compatibility problems.

If you need to see the contact managers, please let me know. Any questions, i will be glad to discuss. Thanks.