Showing two colorbox windows side by side...or within one main frame?
One simple approach would be to just create a content type that includes both items. For instance, "songs". Then, you could:


Embed each youtube video within their corresponding tabs node. 
Then, you could use a module such as Display Suite to display one next to each other (E.g. video on the left column and tabs on the right column).
After this, if you want the tabs to be "scrollable", just set a fixed height in CSS and a "scrolled" overflow. E.g.

.views-field-body pre {
    height: 300px;
    overflow-y: scroll;
} 



That should do the trick, the colorbox will open one node, instead of 2 as currently.