Sorting by most recent date

I really hope you can help me, and save me from a major headache.

My problem is that I have a list of names, grouped into several categories, but the way my system works is that every change to the directory results in a change only from that date. 

f.ex. if Name should be moved from City A to City B, and the change is made on 1 Jan, the new information will only work from 1 Jan, but all data prior to 1 Jan will show John in City A.

I am hoping I can:

1. Take the list I have and group the information so that I have one name, all groups, but only the most recent date of each grouping

   Name	City A	Jan 1
   Name	City B	Most recent date

    

2. Filter the most recent date by name, and remove all groupings before that date
3. Ending up with something like this

Does that make any sense? Please let me know if you have any questions.