Determine If Date Falls Within A Range For Multiple Unique Lines

File A has patients with discharge dates over two years. Each patient may have multiple dates. Example:

Patient Discharge Date
John Smith 7/1/2012
John Smith 10/1/2012
Judge Judy 7/1/2013
Judge Judy 12/1/2013

File B has office visit dates for the patients. Again, each patient has multiple office visits. I need to be able to see which office visits were within 15 days of a discharge date. Example:

Patient Office Visit
John Smith 6/1/2012
John Smith 6/15/2012
John Smith 7/10/2012
Judge Judy 7/20/2013
Judge Judy 12/12/2013

Is there any way to note next to the discharge date that for John Smith the 7/10/2012 office visit was within 15 days of the 7/1/2012 discharge? And the same for Judy with the 12/12/2013 visit?