is the a way to save a selection of photos in a contact sheet to a new contact sheet.
This sort of thing is commonly solved by assigning a particular color class, a star rating, or a tag to the "favorites" and then if you want to see just the favorites, use the widgets (for color class or star rating) or view control (to "view tagged") to filter the contact sheet. (Pro tip: You can option-click (mac) or alt-click (Win) a color or star rating to automatically deselect the other choices. It's faster than clicking each of the other colors/stars)
If you are already using all three of those for other things, another option would be to add the keyword "favorite" to each of your favorites. You could then use "Find" (cmd-f on mac, ctrl-f on Win) in any particular contact sheet to
select only the images with the "favorite" keyword (this could be saved as a snapshot preset in the Find dialog if you use it a lot) and then "View Selected" with the F2 key.
Yet another option is to select your favorites and call up Copy/Move (command-y on Mac, ctrl-y on Windows) and from there you can automatically create a subfolder (perhaps called "Favorites") and copy those images to that subfolder, and then that folder could be opened as a contact sheet.
Perhaps one of these can help you accomplish what you need.
Mick