Extreme Programming Role Compatibility

How should XP roles be distributed in small teams? Some roles can be occupied by the same person, while others cannot.

Compatible pairs:

    Tracker/Manager
    Coach/Programmer

Incompatible pairs:

    Customer/x (where x = Programmer, Tracker, Coach, or Manager)
    Manager/x (where x = Programmer, Tracker, Coach, or Client)

Confused - Tracker/Manager is compatible but Manager/Tracker is not?

What about all other combinations?

Related Wiki:

     ExtremeRoles

---

For more XP Implementation Issues, visit ExtremeProgrammingImplementationIssues