Set average workout on Forerunner

Hi guys!
I am not sure about asking this, I need to set this bike workout on my Forerunner, is this possible?

Bike, cyclo computer not allowed (but smart watches allowed):

  • A cycling trial (as in a race), including uphill and downhill sections. The length of the course is unknown.

  • The rider must maintain an average speed of 15 km/h. The winner is the one who comes closest to this target.

  • No cycle computers allowed; smartwatches are permitted.

  • I need a graphical indicator to show my current average speed compared to the target speed

Thanks.