An effect to replicate Dhampir harmed by positive effects and healed by negative?

[RuleofThree]

I have a Dhampir in a new campaign I am running, and I am honestly dredding having to do this manually because the cleric forgot to exclude him from a Selective Channel, or worse, the cleric doesn't take Selective Channel. Would also help if I have a Negative energy trap, and it knows to apply it's damage as healing rather than harm. I've tried my 'google fu' on this website, and found nothing so far..so here's to hoping I just missed it. Thanks in advance.

[Svandal]

As far as I know this is not possible automatically.

Remember the channel energy, it either damages undead, or heals living, not both forthe same channel.

And for any type of damage, if you hold down (ctrl or alt or shift, I csnt remember) and drag the damage out from the chat it heals that amount of damage.
Not sure if you can drag out the healing from the chat and it turns into damage, have not tried this but I hope it works.

[bmos]

Because, as Svandal says, it doesn't do both but rather either, it's actually not much of an issue.
Just be sure to set up any relevant negative energy spells with extra buttons for the equivalent healing.