Convert table to list

Hi I am having difficulty converting a table to a list. However the table is a database of distances between cities and the list I want to create needs to omit repetitive data (ex since City 1 to City 2 will be listed first City 2 to to City 1 can be omitted). I also want to omit City 1 to City 1 data as it is redundant. I have attached a spreadsheet demonstrating my data and what I am looking for. Is this possible? Any help with be greatly appreciated.

Kevin