You can setup a virtual output as an up next preview - same as what is shown in the Sequencer Preview window when you focus on a take item (highlight it with the blue bar). Or you can set up a virtual output as an up next preview for a specific channel - which will only show the preview frame of take item for a specific channel.
To add a virtual output:
In XPression > Edit > Hardware Setup > Input/Output > Add > Virtual Output
To set the virtual output as a preview:
In XPression > Edit > Hardware Setup > Preview & Monitor > Up Next Preview Output > Set to Virtual Output you want to use
Keep in mind that the up next preview only shows the preview frame of the take item - there is no way to mirror a virtual output to an SDI output.
#XPression