if ( math . random ( 3 ) == 1 ) then 
local group_group = { 
2425 , 2425 , 
2426 , 2426 , 
2427 
} 
local group_num = math . random ( table . getn ( group_group ) ) 
local group_vnum = group_group [ group_num ] 
mob . spawn_group ( group_vnum , pc . get_local_x ( ) , pc . get_local_y ( ) , 1 , 1 , 1 ) 
end 
