I believe this type of expression is what you will be looking for:
( Month('Date by Month'n) In (3, 6, 9, 12) )
Is this the type of result you want?
What I did here was create a duplicate of 'Date by Month' and set its format to Month. This data item is assigned to the button bar. To show only the 4 end of quarter months in the button bar, I created a filter similar to the code I shared above. Then I created an interaction so that the list table would be filtered by the button bar. This might happen automatically for you, depending on how you create the button bar.
Let us know if that helps, or if you are looking for something different.
See how to use one filter for multiple data sources by mapping your data from SAS’ Alexandria McCall.
Find more tutorials on the SAS Users YouTube channel.