What it does
I'm not aware of "Targeting Relay" as an official Magic: The Gathering keyword or ability. It doesn't correspond to any printed mechanic I can verify, so I can't give you accurate rules text or interactions for it.
It's possible this is a misremembered name, a fan-made or custom card mechanic, or terminology from a different game. If you can share the exact card or where you encountered it, I can help clarify what's actually happening.
If you meant a real mechanic, some possibilities worth checking: Replicate, Conspire, or general targeting rules (like how spells with multiple targets behave, or redirect effects). Let me know which you're after, and I'll give you a precise, Commander-focused breakdown.
