Create tasks on the task list page without a contact specifically for your team members. These tasks can be used to manage work and responsibilities within your team easily
Utilize the "Unassigned" option in the "Contact" filter field to filter out contactless/internal tasks for your team.
Along with creating contactless tasks, the contact can be added, removed, or reassigned anytime post a task is created giving you absolute control over managing the tasks in your subaccount