Photos in Timeline

I created a timeline with photos having their duration different from the others. 

Photo 1 is 3 seconds

Photo 2 is 4 seconds

Photo 3 is 9 seconds.

Photos etc.....

I like to have a timeline with 10 photos that I can drop other photos replacing the current ones but keeping their duration. Is there a way to create a preset that I can drop over the timeline that will change 10 photos? Or how could this be done? Thanks