Yes, you would need to merge the two documents in order to be able to use the calibration curves in the one document to calculate the concentrations in the other document.
One way to merge the two documents is with the menu item:
File > Import > Document
The "Import Document" menu item is usually used to merge documents which have disjoint sets of peptides (or molecules) in the two documents, but, in theory, it can also work in your case where the peptides are the same and the replicates are different.

A different way to get the calibration curve samples into the other document would be with the menu item:
File > Import > Results
and then you would need to tell Skyline the concentration and sample types of the newly imported replicates.
-- Nick