Sure. You can set per-branch contexts in netlify.toml (File-based configuration | Netlify Docs), something like this were your branch called “old-branch-1”:
[context.old-branch-1]
command = ""
that will mean that when we see a (dummy) commit on old-branch-1, we “build” by just copying the files, and we then automatically make a branch subdomain (cf [Support Guide] How to use Netlify’s branch deploy feature without Netlify DNS if you aren’t using our DNS) available.