Sheet row number automation

Hello all Excel Gurus,

I am trying to make a macro-free workbook, and am having difficulty in automating its numbering. if you can spot an easy solution i would greatly appreciate it.

basically what i'm trying to do is to keep 4 columns (a,b,c,d) for numbering of items and sub-items, and i wanna number it like the example below:


http://www.flickr.com/photos/66741761@N08/6077998499/


and so on. basically i want each number to be in a column, and the next column would be a sub-heading of it, and its numbering would have a period and have its own numbers. is there any way of automating this without writing a macro?

the problem with this is that this list is always evolving and rows get deleted and added so whatever i do i have to make sure that if i delete a row all the other rows will update themselves properly, or if i add a row in the middle somewhere it follow the proper numbering scheme.

any input/suggestions is greatly appreciated.

thanks