When the first page isn't the first page

So here's a random situation. I'm thinking of putting a submission for my current serial effort in the queue, but it's kind of a follow-up.

In brief, the situation is that I once wrote some short "case files" for my university witch character and her associate, each about four parts in length (under 10k words). I'm now putting online a much longer story (closer to 50k words) that acts as a follow-up to those characters years later. You don't need to read the prior case files (except for flavour), but it means that I have a "Previous" link going back to those stories, because they are in the continuity.

So, the question is, do people think this will this play out okay (both for site administrators and readers), or is it too confusing if the link to "Act 1A" seems to not be the first page? (Certainly the start of this longer story is more dynamic - I think/hope - than the initial shorter efforts.)

I think it might be confusing to have the link read "Previous" because that implies the readers are jumping into the middle...maybe make it "Additional Reading" or something along those lines?