This is a tough call. While many, if not most, of us choose this work because we want to serve others, we MUST develop a professional detachment. You will drown in your feelings if you don't. I think this is such a nice idea with good intentions, but it may have the effect of tethering you to the death instead of allowing you to move on. Paying for the person behind you may very well made you feel good, but it also may bring up a host of other emotions, or none at all. I just question how therapeutic this may be in actual practice, even though the spirit of it is lovely.
I feel like it is more beneficial to develop a self-care ritual, rather than a pay-it-forward ritual, to cope with death where we work. We work each and every day to be kind and compassionate at work, many of us volunteer and commit random acts of kindness, and we all have family and friends we look out for; but all too often we forget to extend that effort to ourselves. I love the ritual one poster mentioned, of eating donuts as a reminder to enjoy life. For me, while it's not a particular ritual, I always try to do something that nourishes my body and spirit when a patient's passing sticks with me - go for a run and be grateful for my body's strength and endurance. Walk outside and enjoy the feel of sunshine and wind or even rain. See my family or snuggle with my boyfriend. Listen to or make music. Whatever helps me to truly cherish my life in that moment.
My last thought is that, depending on the environment we work in, it's beneficial to develop a healthy relationship with death. It's a natural part of life, and while it is sad to lose a loved one, it is not always this horrible, awful fate. Obviously this is not something that, say, pediatric oncology nurses or nurses in the ER will be able to see as a positive thing, and that's today understandable; death can be very, very wrong. But in other scenarios, I think it's helpful to reach a sort of truce with the idea that life ends for all of us and it's okay. This understanding made my time working in hospice much easier; and now that I'm in med-surg, it is still a helpful outlook, even though I want to help all of my patients regain health and quality of life.