Sharing a folder only to a user on another machine

[Pendres]

I need to share a folder on a machine to make a scheduled backup from a server. However I don't want everyone to have access to this folder.
How can I give access to the server Administrator only?

i.e.: ComputerA and ComputerB. I want to share a folder on ComputerA and user \ComputerB\Administrator should have access to that folder on ComputerA.

Thanks!

[Rajesh4mLA]

If you wish to just share the folder with any particular user then just sharethe folder and give full permission to that. Now go to the advance tab and find location. There you have to add that user and it will be done.

[Pendres]

Thank you for the quick reply.
I tried your suggestion and in the Advanced options and location, I tried several options like server/administrator or \server\administrator, etc. and none were accepted.
Note that the network is not in a domain, just a workgroup.

[SpearMan]

Try to create a group with admin as the only user and then make that group the owner of the shared folder. Only admin will have access. If you want the administrator (you) to have access as well add him to the group too.

[Pendres]

My apologies to be such a beginner:
Should I create the group on ComputerA and it will contain the user from ComputerB? in that case how can I add the user in ComputerB to the group on ComputerA?

[EINSTEIN_007]

Follow the below steps:

1. Click Start, point to Programs, point to Accessories, and then click Windows Explorer.
2. Right-click the appropriate folder (for example, Accounts Receivable), and then click Sharing.
3. In the folder's properties, click Share this folder. Use the default name for the share. Click Permissions.
4. In the Permissions for dialog box, click Add.
5. In the Select Users, Computers, or Groups dialog box, double-click the Authenticated Users group, and then click OK.
6. In the Permissions for dialog box, click the Authenticated Users group.
7. In the Permissions list, for the Full Control permission, click Allow. After you have set the appropriate permissions, click the Everyone group, and then click Remove.

[Pendres]

I have done all these. My main issue is that the Advanced Sharing dialog doesn't allow me to add a specific user from another computer.
The desktop is Windows 7 Pro and the Server is Windows 2003 Server.

Please see the attached screen shots: