Does anyone know how to select multiple assignments (in assignments with multiple groups and many assignments)?

I use Cengage and it adds the assignments to the very top group and then I have to move them. I would like to do a multiple select for instance using the Shift key or Control key and them drag them to the correct assignment group. But this doesn't seem to work.

I am dragging them one at a time or using the Move one a time. 

Thanks!