Something like this? Change chance and monster names.
Globalevent.xml
<globalevent name="snowman" interval="80" event="script" value="snowman.lua"/>
local pozycje =
{
{x = 429, y = 438, z = 7, mob="Snowman"},
{x = 390, y = 466, z = 7, mob="Snowman"},
{x = 378, y = 452, z = 7...