CiviEvent price set custom validation rules
You can limit the price options the user sees with some JavaScript in a custom template. This can allow you to control the user options based on the selections. For example:

If the user clicks 'Full Registration' it triggers JavaScript to only show the relevant options. So if meals are included in the user doesn't see the individual meal prices. 

You need to do some planning particularly with required fields. If there is a field that you need to be required that relates to individual items you need to have an option for when it is included in the full registration. This will avoid errors. 

More information on custom templates can be found here: https://docs.civicrm.org/sysadmin/en/latest/setup/directories/#custom-templates

Hope this helps.