Hi @Alejandro_Acin there isn’t a way to do so but feel free to suggest this is a feature in this thread — What features does Readymag lack the most?
I do suggest breaking your project into pages or chapters to help with load times. You can still have key repeating elements pinned to all pages so you only have to replace the page content or by creating a template / duplicating a page to help make the process easier!
If you still are having problems with the length of your project I would also add to help with page loading times to order your project layers into the order in which they are shown to help reduce load times a fraction.