Identifying Combinations

Hello,

I am working with a data set that has names in separate columns. I am trying to identify the existing combinations and name them. I am trying to identify the combinations so I can put the information into a table. I will list an example below and attach a example file as well.

Mike - Tom (Combination A)
Tom - Mike (Combination A)

Bob - Tom (Combination B)
Tom - Bob (Combination B)

Mike - Bob (Combination C)
Bob - Mike (Combination C)

Mike - Mike (Combination D)