I make several types of tickets. I indicate that it is required to collect information about the participants. In arbitrary fields I do a checkbox to pay for additional services. I indicate that the checkbox should be displayed only for the form of group participants. When a participant selects a checkbox, the price increases; if it cancels the checkbox, the price does not decrease. If you select for example 3 tickets and check the box of only one participant, then the additional price of all three participants will be added to the total price. How to fix the error?