Officially the Hue Dimmer Switch is invisible to SmartThings.
There are some community workarounds, but they’re pretty complicated to set up.
If all the devices in your scene are connected to your Hue Bridge (including the Dimmer Switch), it’s pretty easy to set up a time restriction with the third party iConnectHue app ($4.99 as of this writing) or some of the other third party apps. Last time I looked this allowed up to five time slots.
But this won’t include other ST-controlled devices. You could set those up through ST to follow one of the Hue lights in the scene, but there might be a short lag.
I looked at iconnecthue - However its ios only and i’ve only got android devices.
I did purchase one called all 4 hue - which allowed me to create a scene and then set it to work at different times - however after much playing around with it, couldn’t get it to work.