You can use the entire Video lightbox as is by stacking it in a separte <div> container over the top of the other Flash content on the page.
The stacking process is a common practice in HTML and is called z-indexing.
Leave a blank spot in your .fla in exactly the spot you want the video gallery. Place your .swf on the Web page as you normally would. Now there will be a blank spot where the video gallery will go.
Then using z-indexing and CSS positioning, place the video gallery in it's own <div> container stacked over the top of the Flash content. This will make it look like the video gallery is a part of the Flash background.
Here is a working example... the Vimeo player is layered over the Flash background:
more on z-indexing here: