You could use parts of my guide Here to add more Game Masters into the mission. The following is how to do it on Tanoa.
Step 1. Use PBO manager to extract the NMD Sandbox mission files to Documents/Arma 3/missions/NMDSandboxMultiZeus.Tanoa/
Step 2. In Arma 3, in the editor menu, press Ctrl+O on Tanoa (It must be selected)
Step 3. Load the mission NMDSandboxMultiZeus
Step 4. Find where the units are placed (there will be a squad for each indi, blufor ...etc) and make sure they all have names in the Name: field.
Step 5. Place down a module (F7) in category choose Zeus and in module choose Game Master
Step 6. In the name field put in NMD_curator_2
Step 7. In the owner field put in the name of the unit you want to have zeus aswell.
Step 8. put down a Set Attributes - Objects leave everything default
Step 9. put down a Set Editing Costs and set everything under Assigned Zeus to -1
Step 10. Repeat step 5-9 or just copy and paste, 1 game master per player don't forget the two other modules, name the game masters:
CUP_curator_2
CUP_curator_3
CUP_curator_4
and so on...
Don't forget to put unit's names in the owner field of the Game Masters.
Step 11. Save the mission and export it to multiplayer missions
Step 12. in Arma 3/MPmissions will be the .pbo containing the modified mission ready to go.

Doing it this way as apposed to my guide will make sure the AI Bases stay intact. (If there even is any on Tanoa)

Any issues let me know :)