How to map multiple physical directories to a virtual direct

[grece]

I want to map more than one physical directory to a virtual directory.
For example, map c:\xxx and d:\yyy to \zzz.
That is, if a user goes in the virtual directory \zzz, then he can see all files in c:\xxx and d:\yyy.
How can I make this work or you would consider it as a potential function?

[FTP]

Sorry, I think it is impossible to map multiple physical directories to one virtual directory. You can add several virtual directory instead of one.