I want to create a top-level model, then copy those objectives to other models (sheets) within the same file. The other models may have additional objectives as well as the "main" objectives.
This can be accomplished as follows:
Create your top-level document
From the decisionAccelerator menu, "New..." then copy sheet (don't reset the model) - this will essentially copy the existing model
Delete All Alternatives (if necessary)
Add and rank new objectives
The advantage this has is that all your ratings for the objectives + comments, etc. will all be copied over.
This is of course assuming you're starting from scratch. If, however, you have already created the sheets, then you will need to copy-paste. You will need to copy-paste the objectives, pair-wise and the ratings. Copy-paste works fine then click the "Calculate Priorities" button.
Bear in mind that if you copy-paste the ratings, you not only need to copy-paste the type of rating (e.g. Custom) but also the line below (that defines the actual rating). It will look like an empty cell but there is information in there.