Well, there are a few different methods.
Typically, the sites are db driven, which make it easier than if the sites are static.
If the sites are db driven, than you just pass through the same db data to a different "template".
If the sites are static driven, than you need to create the static file with the same code twice. (or create the same code in two seperate files)
If you used the same file, you would use the SWITCH & CASE method.
If you don't use the above, you would just need to get your "news publication" script to write the data into two seperate files.
That is the overview of how to do it 🙂
Later.