I am new to RMXP.
If my memory serves me correctly, in the older RPG Maker titles you could make monster locations on a map.
i.e - An overworld map that has different troops in different places.
This doesn't seem to be in this one... or is it hiding somewhere? It seems like a really big oversight taking that out... it makes overworlds useless as well as taking away a feature useful in many other situations.
Hmm, not sure exactlly what you are saying, im pretty new to RMXP also. But if you make submaps to a big map you can make it so diff monsters appear in the different maps, but i think what you are asking is about zones? if so, i don't known if there is a way.
I mean like having one map and different 'zones' with different monsters. Like on one part of an island you find one set and on another a different set.
Find Encounter Control in here: http://www.dubealex.com/asylum/index.php?showtopic=12209