With only 5 songs, your ear and PGPeakLimit may be the simplest cheapest answer.
Run the other 2 softer songs thru PGPeakLimit and adjust to match the others.

VERY simple method; load Song 1 (louder) on track 1.
Load song 2 (softer) on track 2.
Insert PGPeakLimit in the plugin area for track 2, audition back and forth while adjusting the pregain in PGPeakLimit..

Or whole 'nother route is use the 10 free day trial of Izotope Ozone .. and then try not to buy it once it expires ..
<grin>


I do not work here, but the benefits are still awesome
Make your sound your own!