Drupal CSS - Workaround for background image fixed on iOS Browsers

Hello, i have a Drupal site. In some Divs i use background-image with "background-attachment: fixed;". That does work in Desktop Browsers, but not on iOS (iPhone, iPad, ...). I have seen that could be solved with clipped path or so, i am not a Pro. I do need this workaround for 8 Divs. Please reply how long it will take and how much it will cost. Thanks and best regards, Mario