How to best group interview subjects into “roles” for persona creation?

I’m a designer at a health tech start-up, and I’m currently working on a project to design a Telehealth platform to educate pre-op orthopedic patients, so that they don’t have to attend the requisite in-person joint class. We just kicked off the discovery phase, and as I really want to be thorough about how we’re gathering and synthesizing our user interview data, I’ll be using Cooper’s standardized method for creating user personas.

However I’m a little unsure how to apply Cooper's concept of grouping interview subjects by role - which is basically the first step in persona gen beyond gathering data. In the book About Face, the author says, “For enterprise applications, roles are easy to delineate, because they usually map to job roles or descriptions. Consumer products have more subtle role divisions, including family roles, attitudes or approaches to relevant activities, etc.”

Since I'm designing for the latter, it seems I have to be a little creative with what roles I'm creating and the criteria I assign to them. How have you approached this challenge? Do you have any tips or best practices for grouping users by roles? Thanks in advance!