I completely advise against doing this unless you're testing out an add-on on single player or with some beta testers for an add-on you're working on.
transmitDatablocks();
commandtoall('missionstartphase3');
The biggest problems with this:
If there's content included in the datablocks that a client has not loaded, they will drop out of the server.
Not sure if this still happens, but any new particles will not have textures, they will all appear as squares.
I do not remember the command that updates events.