Creating Parent ID from ID# based on Level number

[Fitz]

Hi, I'm new here -

I have an interesting situation where I need parent id's for a category/sub category spreadsheet that only contains ID#, Category Name and 'Level'. The level column reflects how deep the subcategory is related to the parent, for example a top level category would have a level of '0', if it had 3 subcategories all those would have a level of '1'- however, if the top level category ID is 15, the level id is useless- I need to have the subcategories pull in the parent id# based on what level the category is. I'm working with about 5000 rows so editing by hand isn't an option - is there a handy formula or macro that will straighten this out?

Attached is a small test sample with Category ID (Col A), Category Name (Col B), Level ID (Col. C) and desired Parent ID (Col. E).

Thanks!