You have to use a group policy to achieve that.
You could apply it per VLAN or per user.
Philip, I know I can apply a Group Policy, but you can only apply one GP per device. I was looking for more of a general rule with a schedule. If not possible, please forward as a feature request.
Apply the group policy to the VLAN interface on the MX.
Again, you can only apply one GP per vlan. Think it would be cool if we could add a scheduling feature to traffic shaping. My two cents; something to think about.