This example has the additional children as 'Guests' which ensures the higher child price is selected with additional children at the lower price.  Capacity is shared thus no manual intervention is required.

Great summer camp for ages 8-12, 22nd to 26th July.

First child £200, additional children £160 per child.
Please note that attendance is for the full week. Individual days are not possible.

Fabulous location - Triangle Leisure Centre next to the Sussex Lakes.

Camp T-Shirts can be purchased as an additional item at a cost of £10