one domain inside another(IIS4) DNS

Hi,
I am trying to park one domain inside another.ie; suppose I hace a domain ABC, I have put another domain XYZ inside it, so that i can access XYZ as http://abc/xyz
So far so good…

But I want to assign a different FTP username to the 2nd one, coz I don’t want users of 2nd domain to access first one. I havecreated FTP site with necessary permissions, but could not access it. can anyone tell me the exact DNS setting for this?

Thanks..