voice 3 help

I'm using MS4 and the SATB Closed Score template. I wan't to add some cue size notes for my tenors but it seems MS4 is limited to just voice 1 and 2. I'm using Voice 1 for the tenor notes but if I want to add some extra notes for tenors and make them cue size MS4 wants to change voice 1 notes to cue size.

Is there a work around for this? In the image attached I just want the notes in red to be cue size.