Track Hours by Users Role

Hi,

I need a way to separate a users hours when they either are promoted to a different role or they switch teams within our group.

Right now all time is tracked by the user's profile. Lets say Sally has been working with the digital team for the last three years and we've been calculating all her hours. Due to some rearrangements within the department she has now been transferred to the Operations team.

If I want to do a comparison to see year over year where hours are being spent, Sally's hours from all three years will now be included in the Operations team even though she just joined the team and the digital team's hours will go down because they are missing the hours Sally spent with digital.

The timelog categories are not an option because we use this for something else. 

Is there a feature that can allow for this? My thinking is a dropdown on the user level that carries over into timelog reports, similar to when you update dropdowns and all previous entries stay the same but future entries take on the new selection.