The ability to use external data in an Axure prototype has been a long-standing request, and I think a kind of line in the sand that Axure does not want to cross. So you’re pretty much left to using global variables, or perhaps finding a way to hack in some javascript to handle this, and getting around browser security restrictions. For example, here is an old thread that claims to accomplish similar: Skip the Repeater. Learn how to use Google Spreadsheets as a database instead
A workaround would be to fake your separate pages as different states in a dynamic panel. So, if you have three pages in your prototype that use the repeater, create one page with the repeater, and with one dynamic panel for the rest of the (unique) page content that has three states, like “Page 1”, “Page 2”, Page 3". Whenever you would load one of these pages, just change the state of the dynamic panel.
A similar workaround would have one repeater and one Inline Frame widget on the page, where the unique page would load in the inline Frame.