The thing is, doing a Windows search for "LAI_MONSTERS_GROUP" turns up a few hits in "PROGRAM\Loc_ai". Searching for "monsters" gets a lot more hits, most referring to the locator group rather than the LAi group. The one time I found something actively being assigned, it was in "quests_reactions.c" for "standard", case "monster_generate_in_alcove":
In fact, I wasn't sure what the group name was either, at first, so I searched for keyword "monsters", ignored everything that referred to the locators, found that piece of code, and that's why I thought 'LAi_group_MoveCharacter(ch, "monsters");' would be right - someone has already used it.
Code:
case "monster_generate_in_alcove":
//ChangeCharacterAddressGroup(pchar, "Treasure_alcove", "teleport", "teleport0");
LAi_group_SetLookRadius("monsters", 30.0);
/*NK*/ sld = LAi_CreateFantomCharacter(false, 0, true, true, 0.25, "mummy", "goto", "monster1");
LAi_group_MoveCharacter(sld, "monsters");
/*NK*/ sld = LAi_CreateFantomCharacter(false, 0, true, true, 0.25, "mummy", "goto", "monster2");
LAi_group_MoveCharacter(sld, "monsters");
/*NK*/ sld = LAi_CreateFantomCharacter(false, 0, true, true, 0.25, "mummy", "goto", "monster3");
//LAi_SetMonkeyType(sld);
LAi_group_MoveCharacter(sld, "monsters");
LAi_group_FightGroups("monsters", LAI_GROUP_PLAYER, true);
break;