Sorting Text alphabetically using last word before comma

I'm currently ordered to sort a list with ~250 entries alphabetically. Problem is: Not using the first word(s), or a specific column, but using the last term before the first comma:

[li]title suame1 name1, occupation, city[/li
][li]title suame2 name3, occupation, city[/li
][li]title suame3 name3, occupation, city[/li]

I'm currently trying to not do this manually. Any idea how to do this?