I don’t believe it’s possible at this time to forward emails to “My Tasks” on multiple workspaces. Has anyone found a workaround for this or is this a feature that would potentially be worked on?
To create tasks in your My Tasks list via email, send an email to firstname.lastname@example.org. By default, email@example.com will create a task in the Workspace or Organization associated with your email address.
So, if you have a workspace under a different email address, then this is something you could do.