You may create a dummy expression with a value of chr(9474) which is unicode character for vertical line.
For label, if it is 3 line high, you may use chr(9474)&chr(10)&chr(9474)&chr(10)&chr(9474)
You may adjust the expression for the label depending on the lines in the header as needed.
If you use space (' ') as your dummy expression, you may play with background color.
Hope this helps.