This is super easy!
SetEnemyDisableTriggers(string& asName, bool abX);
It's as easy as that! LOL
Okay, so when you activate the monster, put that little baby into the function:
string& asName is the name of your monster (with quotes) and
bool abX would be true (no quotes).
This particular line disables the enemy triggers, which, as you may have guessed, disables the monsters reactions to the players. That means, should your player walk close enough to it, make a noise or technically "be seen" by the monster, he won't do a single thing.