Hello to all. This is a relatively simple evolution to make to the YouTube widget. I would suggest that adding a “Group” attribute to each video link would be a simple way to “filter on click” each video by its affiliation to a specific group. This feature is already used in the Team widget with locations like Los Angeles, Sacramento and so on. You click on the location “Group” and it filters out all the other locations leaving only the location that is included in the “Group” that was clicked. So if I have say three locations, “Los Angeles”, “Sacramento” and San Diego" and I click on the group “Los Angeles” then all the users in group “Sacramento” and “San Diego” are removed from the view of the end user. In this same way you could apply this “click on Group filter” tool in YouTube videos widget so that an end user clicks on the grouping he/she wants … and all the other YouTube videos are removed from sight …
Greetings @Panos_Marcoullis 
We are so glad that you’ve decided to join our Community! Welcome aboard 
I have to say that YouTube Gallery widget has Source Groups option that allows you to add single videos and playlists as well. Here is an article that explains everything in more detail - Displaying YouTube playlist in Youtube Gallery widget - Elfsight Help Center
Please check this feature and let me know if it suits your use case 