(Pre-)Roll for Initiative

If I am DMing and I create a map with 20 monsters on it, I should be able to roll for initiative during my prep time, and have the initiative rolls retained *on that map only*. That way, when I drag the players on the map, only they need to roll for initiative, and I do not need to roll 20 times in front of them, which takes forever. Then once I drag them to a new map, I should be able to drag them to another map where I have already rolled for initiative. Basically make monster initiative rolls part of the DM's prep time rather than something that happens during gameplay. 

Hi Nikolai C.  You can already do this. Initiative rolls in the Turn Order are on a per-map basis. Only the GM sees them.  Additionally, since you have a Pro account you might use an API Script to roll many creatures at once. GroupInitiative for example.

Yes, I do this all the time. The players will only see the initiative results for the NPCs on the current map (and only the ones for NPCs that are on the token layer) Initiative rolls for those on the GM layer and on other maps appear only to the GM. The one inconvenience with doing this is that you'll be advancing the Initiative past all those "invisible to the players" entries while the players will only see it advance to the next entry that they can see.