You can assign a collaborator to each page easily in Pages. (Keep in mind – you have to have already invited people in Manage Team and they need to have already activated their accounts.)
In your Kit, click on Pages. There is an assignee dropdown you can use to assign a person to that page. Click on No Assignee to assign a collaborator. (Likewise, if you click on the Page name, there is a dropdown in the Page details to assign a collaborator.)
To reassign, click on the dropdown and choose a different person.
To remove that person from that page, click the X icon next to their name.
You can also manage the Assignee from within the Page details itself: