It sounds like you receive a zip file containing several files. I'm guessing that the intended use is for you to unzip them all to a single location on disk? I would suspect that the reference sheet assumes that the target files will be in the same folder (or in folders below if based on the structure of the zip file). I would expect that those links will no longer work if you just import those documents as-is into your repository. The target documents are no longer "in the same folder" in the way that the links need them to be in order to work.

The two main options I can think of are 1) import the entire zip as a single entry. You'll need to download the whole thing in order to access it, but everything will stay together and the links will work as they do now. 2) Import them separately, and use Laserfiche document links to hook the other documents to the reference sheet. Depending on how much context the reference sheet needs to provide, the user experience here might not be as good. This linking would be a manual process.