well its really cool, what i did was i made an event, that for each "enemy"(family), and second condition, every random(2000) milliseconds. set private variable "move" to random(2)
this will mean that for every monster that u have in the family, it will set their own private variable 0 or 1 at their own random time
make some events for the family such as if private variable "move" is equal to 0 then set angle to 0
and make the same for 1 to equal 180.
i did it for my game and i also gave them a line of site with a range of 250 and once in LOS they would act like the kooper monsters in the platformer game. ill upload a cap of my game to show u, but u are WARNED: i dont excercise organizing my events very well lol.
the example is on layout two, ull notice that all of them are same monsters in random patterns and ALL of them walk independantly even when each monster is just another instance of the first ones i created