Here are some links that can provide further ideas about enacting this service:
God of the Dark and the Light
Blue Christmas, Year A
The Christmas season is often presented as unending joy and peaceful family celebration from beginning to end. There isn’t much room for grief, for a sense of loneliness, or for any other emotion considered to be negative. Except, emotions aren’t negative or positive; they just are. Here space is created to allow participants to feel what they feel and to be accepted for that.