You can only see the best spectrum for a peptide in Panorama. The "best" spectrum is determined by Bibliospec/Skyline so I don't think there is a way to change it. You may want to ask on the Skyline support board, though. For now, you (or your collaborators) will have to download the file from Panorama and open it in Skyline to view spectra from other replicates.
Panorama does have all the information (spectra from all replicates, replicate names and RT), though. So we should be able to add an interface for users to be able to view spectra from other replicates as well. And we will add the replicate name and RT to the spectrum viewer. I have added it to our TODO list and will let you know when it is available in PanoramaWeb. Thank you so much for bringing this up!