I am looking to include another survey within a survey but want to only reach a certain number of surveyors. Is there a way to set that up within the survey? If not, how can I make it so that I have an additional survey within a required survey so that we can ask optional questions?
You may consider using the Branching Action:
The second survey can just be a specific page or set of pages in the first survey (within the Branching, you can set up a rule to show the page(s) to 10% of the respondents whereas the remaining 90% does not see the page).
Hope this points you in the right direction.