I facilitate both Family Constellations group workshops and also one on one Family Constellations sessions.
Family constellations is a therapeutic approach to shine light and make visible unseen connections, bindings and entanglements of a system. Family constellations work can take place in any system: Intrapersonal, Interpersonal, Family, Intergenerational, Ancestral, Societal & Global. 
A family constellations session typically takes place in a workshop made up of a group of individuals who are not related (even though people who are related are welcome to attend together). Workshop participants are chosen as representatives for members of the system that is being explored. Just by stepping into the role, representatives can feel and experience the emotions of the person whose role they have taken on. Hellinger, the developer of family constellations, calls this sense of connectedness, which is said to be felt telepathically by members of the group, the morphogenic field or the knowing field. 
In the one on one sessions, we use dolls instead of live representatives.
My deepest gratitude to my Family Constellations teachers: Maria Dolenc and Mark Wollyn.