You can definitely do what you’re looking to do using master pages. It just requires correct setup of master pages, frame chains, and flows.
You can add notation information flows to master pages using a master page frame chain(s), but you probably want to uncheck those flows from the “main” master page frame chain (usually MA) if you don’t want those flows also to appear at the end of the layout.
So e.g. have the flow(s) that contain the complete music in the MA frame chain, then have your front matter music shown in a separate frame chain, e.g. MK or whichever gets created - when you draw in a music frame on a custom master page, it should be in a separate frame chain to the Default page anyway; if not, unlink it to add it to a separate master page frame chain. Then edit the Default master page, and untick any flows that aren’t “complete music” from the MA frame chain.
Here’s a quick example project so you can take a look at how I’ve set up the master pages and frame chains to produce the desired result in the Violin part.
front_matter_master_page_example.dorico (399.7 KB)