execute at @e[type=zombie,tag=!nocusmob] run scoreboard players add z skeletonk 1
execute at @e[type=zombie,tag=!nocusmob] if score z skeletonk matches 2.. run function rfi:mob/zombie/zombiekill
execute at @e[type=zombie,tag=!nocusmob] run tag @e[distance=..1] add nocusmob