In Flames by Nicole Northwood

When Seraphina Fox, a medical student at Kestral Medical College for the Supernatural, accidentally uses her matchmaking abilities to pair with both of her incredibly alluring dormitory neighbors, Alexi Bonneau and Dario Accardi, she thinks that she’s made a mistake that could cost her reputation.
However, in trying to decipher her attraction while denying her skills, Sera uncovers a secret through the ghost of a past student and fellow matchmaker: the ability to pair soulmates is rarer than she thought, and the college is working to study the blood that can predict the future of relationships. As Sera, Alexi, and Dario find themselves in the middle of a love affair, feigned death records, and an appalling research trial of what it means to have humanity, they must search out the truth before Sera loses everything… including maybe even her life.