Using the same/connected planner on multiple Sharepoint websites

Hi Alexander25,

Here is an idea what you can do to make your idea happen:

1. Create a Microsoft Team: Head over to Microsoft Teams and create a new team. Add all your team members to it, and don't forget to add the Main Planner as a tab in this team.
   
   Create a team from scratch in Microsoft Teams - Microsoft Support
   Use Planner in Microsoft Teams - Microsoft Support
   
   

2. Add SharePoint Sites: Add project Sharepoint sites as tabs in the Microsoft Team.
   
   Add a SharePoint page, list, or document library as a tab in Teams - Microsoft Support
   
   

3. Main Planner Magic: In each project SharePoint site, add the Main Planner as a tab. While adding the tab, choose the "Planner" option and select the Main Planner from the list.
   
   Use Microsoft Planner on your SharePoint site - Microsoft Support
   
   

The Main Planner will be right there on each project SharePoint site, thanks to Microsoft Teams. What's even better is that any changes you make in one project site will automatically sync and update the Main Planner.