Blocking File Transfers for specific users or computers

According to the Symantec Web Gateway documentation, file transfers can be blocked by adding an entry to the Blacklist... to block the downloads of executable files for example.

It's my understanding that Blacklist entries are "global" (affects all users and/or computers).

But is there a way to block downloads of executable files for specific groups of users or computers, but allow the downloads of executables for other users or computers?

In our particular case we want to block downloads of executable files for all users except those in our IT department which need to download software, drivers, etc. on an ongoing basis.