Additional users on Windows

I have a customer who is building an ASP.Net 2.0 administrative interface to upload images to another folder via the web. Normally, I just lock down the folder this interface is located at, and the user they log into has modify access to upload whatever they want to wherever they want on their site. However, they are now asking me if they can have 2 users that have this ability. This is “sort of” like the additional FTP account, but it isn’t via FTP, but rather via HTTP upload. Can this be done?

Thank you,
-Ben

I cant be done with ASP.NET as it will lock to the application folder, but ti could be done with ASP in the hsphere we use now, but will break with hsphere 2.5 or 3 when we upgrade, right now asp uses the ftp user for authentication purposes and can access multiple domains, they change to use one user for each domain in the newer versions(which is a messy process and one reason we have not plunged yet, the change causes MANY problems)