SQL-Server Procedure for Parameterized GROUP BY Without Using Dynamic-SQL

SQL SERVER Procedure:
Parameterized GROUP BY Without Using Dynamic-SQL : the "impossible" is possible.
NOTE: This procedure and source code builds upon my previous parameterized ORDER BY without using Dynamic-SQL examples:

SQL SERVER Stored Procedure (SP): Parameterized ORDER BY without Dynamic-SQL - Example 1
SQL SERVER Stored Procedure (SP): Parameterized ORDER BY without Dynamic-SQL -