Auto Numbering Across Sub-Sections

[Nonoffensive Name]

Please forgive me if my terminology is incorrect. I've attached the sheet I'm working on but my question is this. Let's say I have 4 subsets of data, and the 4 headings I have are Apples, Oranges, Grapes, and Pears. Under each heading, Apples for example, I have listed different types of Apples (Golden, McIntosh, Granny Smith, etc). The same is true for each fruit. I want to have a column called Item, which will be numerical. In apples, there will be items 1-7, In Oranges 8-12, Grapes 13-20 and so on. When I insert a row into Apples, it will automatically change the item number in the 4 different groups so there are no duplicate item numbers. Now, if everything was in a row, I know that I could use auto-count and when I added a row it would automatically adjust, but I have gaps in between my data groups and I don't know how to make it automatically adjust like that.

Thank you in advance.