How to tip hotel kitchen staff for doing special requests

Factual Questions
1

Question for someone who has worked hotel kitchens:

When I made special requests on my room service order (and, I confess, I often do, but mostly minor things like leaving a few ingredients off a specialty sandwich, or substituting veggies) I always tip extra to make up for the hassle.

However…does any of that money actually go to whoever took the trouble to make my sandwich without the pickles and onions? Or does the delivery staff get it all, despite their not having to do any extra work?

If the latter, any reasonable way to go about rewarding the right person?

2

It would be hard in a larger kitchen to know who made your order, but you could always give it to the person who brings the room service in an envelope and ask that they deliver it to the person who prepared your meal.