The new system DOES allow you to register multiple children in one single transaction. To do so enter the first child's information into the system and input the corresponding fee for that child into the fee field. For instance (if the cost of 2 participants is $180 you would enter $90 into the fee field for the first child and add to your cart. You will see the below message.
<-------- TO ADD ADD'L Child Click here
To add the additional child simply click on the "I want to find more invoices" button located below the checkout button and select Marion Recreation which will bring you to the screen to add additional information.