When I need to do this, I put the page(s) in a hidden folder, then use two Wayfinder calls in the sitemap, one for the main part and the second to get the content of the hidden folder. With proper styling you can’t tell that it’s two lists.
I usually do this for a "legal" section, which menu goes in the footer, like Terms & Conditions, Privacy Policy, etc. I have a container named "Legal", with for example an ID of 5, that is set to not show in menu, so it doesn’t show up on the main menu. I put those pages in that container. Then for my sitemap:
[[Wayfinder? &startId=`0` &outerClass=`outer` &removeNewLines=`1`]]
[[Wayfinder? &startId=`5` &outerClass=`outer` &removeNewLines=`1`]]