Writing a conditional remove duplicates statement in Excel based on values in other columns

I'm trying to remove duplicates in a column based on values in other columns. What I'm trying to do is have Excel spot duplicates in Column A, then within a group of duplicates, delete those which don't contain a certain value (x) in Column B. However, if there are no records within a group of duplicates that contain value (x) in Column B, then delete all except one.

Any help on how to write a statement that could execute this task is appreciated, thanks.