This one has had me stumped for the last few hours and at this stage I think I need some help...

I need to compare multiple groups from a single table and to identify where items listed in col B match. For example: -

```
Col A...............Col B
John................Apple
John................Orange
John................Banana
Mary................Orange
Mary................Strawberry
David...............Apple
David...............Orange
David...............Banana

```

I want 'John' and 'David' returned because their items in col B match. Hope this makes sense!
Thanks in advance!
G