For future readers:
Please use the filter as documented here: http://www.advancedcustomfields.com/resources/filters/acfvalidate_value/
You can apply if to 1 of the 10 fields and within the function, look at the $_POST[‘acf’] array. You will need to find the field key’s for each of the fields and then loop over them to check if one of them contains a value.
If nothing is found, simply return false or a custom validation message.
Hope that helps
