Rule 712.21d

If multiple replacement effects could be applied to the event of a melded permanent leaving the battlefield or being put into the new zone, applying one of those replacement effects to one of the two cards affects both cards. If the melded permanent is a commander, it may be exempt from this rule; see rules 903.9b–c. Example: Leyline of the Void is an enchantment that reads, in part, “If a card would be put into an opponent’s graveyard from anywhere, exile it instead.” Wheel of Sun and Moon is an Aura with enchant player and the ability “If a card would be put into enchanted player’s graveyard from anywhere, instead that card is revealed and put on the bottom of its owner’s library.” If the controller of Chittering Host is affected by both cards’ effects, that player chooses one effect to apply to the event and Midnight Scavengers and Graf Rats are both moved to the appropriate zone.