Sorting Data with Unevenly Merged Rows

I'm trying to create a sheet with employee information that can be sorted and has rows that contain unevenly merged cells.

For example, columns A:D contain information such as employee ID #, hire date, name, and birthdate. Additionally, there is a column that lists different in-service training classes attended. Some employees would have 3 courses completed requiring 3 rows of information, and some may only have 1 course completed only requiring 1 row of information. I would like to be able to sort by any piece of data in the sheet, but am having trouble figuring it out.

I'm trying to avoid repeating the employee information on each row by merging the rows of information for an individual in columns A:D since those will remain constant. However, the column after this will vary and I would like to be able to sort and match this column with the first 4 columns so I can look up by the course or by the employee info.

I attached an example of what the sheet would look like. Thanks any help you can provide.