Assign task to a member of AD Group

Question

Ok here's the situation:

I added an AD group (ADGroup) to my Sharepoint Group (SPGroup), the users in ADGroup now can login to the site successfully but I cannot assign task to any user in a group, unless I add each user directly to SPGroup.

Is there any way to assign task to user in ADGroup directly without the need of adding each of them to SPGroup ?

Thanks a lot.