Joomla / Viruemart Custom Modification

We have a highly customized eCommerce website built on Joomla and Virtuemart. We recently had a developer implement a custom modification to prevent pricing from showing on "Category" page views for products that have "Items" listed under them. For example, Product A is a rope and is available in 5 lengths. "Rope" is the Product and each of the 5 lengths is a different item in order to show stock-on-hand for each variable item. The product "Rope" does not have a price assigned, and no price shows on the Category page for "Rope. When the product is clicked, the items each show a stock-on-hand amount as well as thier own price and "Add to Cart" button. The job was completed and the results were as requested, however one aspect still needs correcting. Since the "Parent" product never shows a price - only the "Child" items have pricing shown - then we do not assign pricing to these "parent" products. But if these parent products do not have pricing assigned, the unintended result is there is no "Add to Cart" option for any of the child items displayed. Only by assigning a price to the parent product will the "Add to cart" buttons appear for the child items. This must be corrected so that we do not need to have any price assigned to the parent product, but the "Add to Cart" buttons will still show for the child items. In your response, please confirm that you are familiar with both Joomla and Virtuemart, and have the ability to investigate the current customized code to find and effect the changes needed. We cannot loose any of the existing functionality! Thank you.