Need forumla to sum number of unique values in groups of different sizes

Hello,

I need to find a way sum the total number of unique positions in the "status" column for each expedition (each expedition may have a different number of people in it). I have attached a sample spreadsheet with the raw data I need help with.

I have indicated my desired output in the attached sample spreadsheet.

I would be extremely grateful to anyone who can help. Thanks so much!!