Hi @Perry_Statham ,
Happy to help!
Audience Specific page SSO can be looked into more here https://support.atlassian.com/statuspage/docs/require-saml-for-audience-specific-pages/, but this separate from the SSO you'll use to provisions SP Admins/Team Members via Atlassian Cloud. SSO implementation here is governed by having User Groups set up for each respective page, and then using the External Identifier as a means of associating that group with the appropriate page for access.
If this is something you'd like to pursue for your site, I would recommend reaching out via a Support ticket since there is possibly some set up to be done from our end as well.
Please let us know if you have any follow up questions!