The Finale SMP export does not currently have the ability to show small ensembles on screen simultaneously.
You can create SMPs with polyphony on a single staff, allowing you to see the other parts. However, SmartMusic prefers to see a single melodic line and you may see your assessment results drop.
Feel free to submit a feature request to us by logging into your account in SmartMusic and choosing 'Give us feedback' near the top right.
These on-line forums are intended for the exchange of ideas among the users of MakeMusic products. If you'd like individual help from our technical support staff, please contact us directly at www.smartmusic.com/support.