Read Domain Name from FMS3

Hi, Can we read Domain name like " http://domainname.com" from where our swf is placed for security reason.

Like i placed my main.swf in a domain xyz.com. And xyz.com (which have main.swf) is accessing my FMS path. then i will allow that swf to enter in our FMS code. otherwise i will block that.

So is it possible to read the domain name of main.swf file from where FMS is called?

This will basically prevent the hackers to load FMS data in their main.swf or any name .swf file. Please help me out.