Wow!  What a long subject line!  But I think it actually captures exactly what I am trying to do.  I am a beginner, so please bear with me.
I have a dataset where one of the variables is 'SupervisorName'.  What I would like to be able to do is count the number of times that a particular supervisor name occurs and delete all records which contain a supervisor name that doesn't appear more than 4 times in the dataset.  
Example  Dataset (this data has already been read into a SAS dataset):
Jim  3   4
Jim  4  5
Jim  6  7
Jim  6  8
Jim  3  2
Suzy  3  1
Suzy  2  1
Given this data, I want to delete all records which have Suzy as the supervisor since she occurs less than 4 times.  Leaving only observations where Jim is the supervisor.  This is just example data, the dataset I will be performing this on has  hundreds of observations.
Thanks you so much for the help!
-jeff