Dynamic list of values based on dataset

I am trying to create a dynamic list of unique values, based on the value of a single cell that can be found in the dataset being used.

My dataset is 2 columns:

Pool Manager
1 John
1 John
1 John
1 Mike
1 Mike
1 Cary
2 John
2 Mike
2 Lester

So, if I enter 1 into the reference cell, I would want a list to say John, Mike, Cary....if I enter 2 I would want the list to be John, Mike, Lester.

There can be multiple values of the same Manager per pool, but I just want a single output of the manager name.

This is going to be based on a list of over 1,000 rows, and 30 different possible pools. Please advise, and let me know if anything is unclear

Please see attached. Let me know if this is what you're looking for.

Thank you for this hoyasaxa...however, I was hoping that the ouput would be unique values. When I enter 1 there are 3 Johns and 2 Mikes, I would only want 1 mike, 1 john, 1 cary.

Thanks again!

See attached.

Perfect! Thanks again!