I don't see a subforum for quest discussion, but new functionality has been merged to allow entity-based access to quest globals on NPCs and Clients, you can take a look
here.
This will allow you to do group flagging with quest globals, check groups quest globals, or check NPCs quest globals, all of this can be direct or it can be routed through the entity list.
If you have any questions or would like any examples of uses for this, just ask. I wanted to get this functionality into the main source as well as get it known that this is now possible, as I personally believe something like this will be much more helpful than having to write a workaround when checking multiple clients' or NPCs' quest globals.
This is also highly efficient, as it makes use of the already stored memory, meaning there aren't any database hits required for this, also meaning that as you set a quest global it can instantly be accessed using GetGlobal.
Thanks for taking the time to read!
TL;DR:
New Quest Global Functionality