Is it possible to create General Task List without inputting Planning Plant?

Hi,

We have a requirement where our client wants to create a General task list which should be common across all the 400 plants. In other words, they want to create only 1 general task list without inputting the planning plant field and if any modifications in future, they want to change it at one place instead of changing for 400 task list for each plant.

I see that the Planning plant field is mandatory in case of general task list and wanted to control via SPRO influencing "A" tasklist type. However, I see that is not possible.

Can you please let me know how can we make this planning plant field optional in case of general task list?