If you are planning on using the 'relay' method posted above, it is often a good idea to either
1. Assign the Command to the Module
or
2. Assign the Command to a High AI Level NPC. AI Level affects priority to a 'n' degree, which might help keep accuracy with DelayCommand actions.
I wouldnt recommend assigning commands to the placeables - in large modules, Placeables get a very low priority as far as Bioware Scripting goes. Even Shayan's Subrace Engine 3.x (the subrace clock) fails to work in Modules that are massive, because the Subrace Clock placeable, is unable to fire off its script at the right time. (without using Pseudo-HB's)
Having a Single NPC with a Maximum AI Level set, in an area that is unaccessible, and assigning all your action/commands through them, would be able to accomplish what you need.
I use a similar method for Server Anouncments.
a Function that does
void MakeServerAnnouncement(string sName, string sMessage);
sName - The Function does a 'SetName' call on the Announcer npc, to make them have whatever name I want.
sMessage - Is Shouted after a 0.5 second Delay - (to allow the SetName to take effect)