Child Price not required for one tour

I have a number of Tours, but the tour in question is for adults only (Corporate Adventure Tour).
My problem is that I can have children on all the other tours and therefore a price can be added for the child. But for this corporate tour, there is no price for a child, therefore, the system enters a percentage of the adult price.
Is there a way to override this for tours not allowing children?
Thank you.
Alan