The somewhat tricky part of this is that you need to create and upload both albums before you go back and add the web locations. Web locations don't work properly if the targets haven't been uploaded yet.

So here's the drill:

Create the main album, without any reference to the videos, and upload it. In my demo, that's the tigerImages album, with two folders of regular images (Saturn and Jupiter).

Create the videos album, without any reference to the main album, and upload it. In my demo, that's the tigerYT album, with just three YouTube videos (no folders), no automated slideshow, different display of title and comment, and so on. You can refine all of that later, if you like. One thing you can also do at this stage is add the "home" link to it. See the homelink screenshot.

Now go back to the tigerImages album, and add the tigerYT web location at the top level, next to the Saturn and Jupiter folders. The target needs to be the full URL, like https://jefftucker.jalbum.net/tigerYT/. Tell Tiger to include web locations in the top navigation bar. See the topbar screenshot. The Explore view of tigerImages should now look like the tigerimagesexplore screenshot. Make the album and upload it.

Finally, return to tigerYT and add the tigerImages web locations. This is needed solely to get the folders of the main album to show up in the top navigation bar of the videos album. Otherwise, you could skip this entirely. So, I've added two web locations, one for each of the folders in the main album, using the full URL for each, like https://jefftucker.jalbum.net/tigerImages/Saturn/ and https://jefftucker.jalbum.net/tigerImages/Jupiter/. For consistency (so that the top navigation bar always shows Saturn, Jupiter, and Videos), you should also add a web location for the tigerYT album itself, as https://jefftucker.jalbum.net/tigerYT/. The Explore view will now look like the tigerytexplore screenshot.

As in the main album, tell Tiger to show web locations in the top bar. But in this case, you don't want thumbnails for them to show up, which would be very confusing for the visitor, so you need to hide them. See the hideweblocs screenshot. Make the album and upload it.