!! You can now create a new plan within an existing group!!
Once you open the “New Plan” dialog just select the link to add to an existing group. Your new plan will then be added to that group, leveraging the existing group infrastructure.
For more info, checkout the support documentation: https://support.office.com/en-US/article/create-a-plan-in-microsoft-planner-93e65b03-6fac-4661-a502-e3161475ab93
An error occurred while saving the commentFlo commented
It would be very helpful to have the same feature to copy a plan to an existing group. At the moment there must be a new group for every copied plan. That's a huge disadvantage of the copy function.