[One Identity Manager 9.3] Best way to store and sync extra attributes from source system not available in UNSAccountB

Hello everyone,
I'm working on an integration with an external database in One Identity Manager 9.3, where I'm synchronizing accounts into the UNSAccountB table. However, the source system contains several attributes that do not exist in the standard UNSAccountB structure, such as email, employeeType, and others.
I'm unsure about the best approach to handle these additional attributes without breaking alignment with the 1IM data model and while maintaining object integrity. I also need to be able to synchronize these additional attributes into the Person table after syncing to UNSAccountB (or whatever the best solution may be).