Many specific groupings exist in the Ivy universe. For better understanding of the dynamics of the character interaction, it is good to know what character groups are associated with each other as units.

The Pre-House Group: Weaver, Dax, Alix, Adele, Neptune, Ivy, Tab, and Thursday. These eight characters came together in the order listed here and made their living off the land. They arranged for the house to be built and later filled it up with roommates.

The Post-House Group: Weaver, Dax, Alix, Adele, Neptune, Ivy, Tab, Thursday, Robin, Zeke, Peyton, Bradleigh, Cecily, Keenan, Perry, Zoe, Nina, Bailey, Miki, and Jared. This is the member list of the house at its highest capacity.

Ivy’s School Friends: Ivy, Andrea, Mandy, and Nicky. They were in ninth grade at Sands High together and still go out as a group now and then.

Ivy’s Immediate Family: Meri Lin Ling (mother), Fred Fisher (father), Ben Fisher-Ling (brother), and Ivy.

Ivy’s Extended Family: Mother’s side: Mother’s parents are Sheng and Xiao Chen Ling. Mother’s younger sister is Lissa Lee Ling: Unmarried, no children. Father’s side: Father’s parents are Neil and Louise Fisher. Father’s older sister is Dorothy Applegate: Married to Dennis Applegate, with two sons, Sam and Loren. Father’s younger sister is Carol Kirkpatrick: Married to Dean Kirkpatrick, with two daughters (Katie and Elise), and a son (Peter). Father’s younger brother is Art Fisher: Married to Camilla Fisher, with one daughter, Cara.

Handprints Members: Ivy, Nina, Max, Nicholas, and Bailey—original five from Book 4. In Book 5, Skyler is added. Later in Book 5 a new member named Grace is added.

Natalie’s Club Members: Natalie, Crys, Gloria, Abby, and Brenda. Monique is not a member but they’d like her to be. Ivy is a temporary member.

Ivy’s “8 Families”: 1. Her flesh-and-blood family (Meri Lin Ling, Fred Fisher, and Ben Fisher-Ling). 2. Nina Fairchild's family (consisting of Nina, younger brother Erik, older brother Jeremy, and parents Francis and Carl). 3. The clan at the house (Dax, Weaver, Alix, Adele, Neptune, Tab, and Thursday, plus the roommates to greater and lesser degrees). 4. Bailey Parker (sister relationship). 5. Max Jacobson (common situational family bonding). 6. Ruben Redwing (partnership, almost boyfriend-like without the romance). 7. Margaret Falconer, a.k.a. "Miss Margaret" (foster mother, almost). 8. Nicholas Chamberlain (common situational family bonding).