Razer Naga Pro with Synapse 3 key

I have a Razer Naga Pro with Synapse 3. I was wondering if it was possible to assign multiple modifiers to a single button. For example pressing a button simulates Ctrl + Shift. I have tried to assign that to a macro but I can't seem to get it to work properly. Either the modifiers persist after the button is depressed, or they stop working before the button is depressed. Pressing two buttons that have each been assigned to Ctrl and Shift respectively works perfectly but I would like it to be assignable to a single button.