I think this could be done using Javascript. If you don't want to use JS, you could just add a link called "More Info" that will open a new page showing all the details.
If you want to use Javascript, use the innerHTML element. Here's an example:
<script>
//You'll need to use some if's here to check IF a race has been selected, and if so, what to show.
document.getElementById('raceInfo').innerHTML="Put your race info/html in here."; //This line will set the html in the div below to whatever is in between the quotes
</script>
<div id="raceInfo">Select a race for more info.</div>