Cell reference formula within formula to pick out a group of similar rows

[derekkil]

Hello
I have a table with 1000+ rows. One column is the Item Name. Each Item Name is unique, but will appear in 8 to 15 rows contiguous of data (before going to the next item name), the number of rows in each dataset can vary.

I need to apply a formula (LINEST, etc) to that only references each Item's set of data. So I need some formula help to make a cell reference that starts at the beginning and ends at the end of the Item's set of data.

Thanks
Derek

[TABLE="width: 267"]
<colgroup><col><col span="2"></colgroup><tbody>[TR]
[TD]Item Name[/TD]
[TD]Data 1[/TD]
[TD]Data 2[/TD]
[/TR]
[TR]
[TD]10L-101-1[/TD]
[TD="align: right"]20.0[/TD]
[TD="align: right"]1.75[/TD]
[/TR]
[TR]
[TD]10L-101-1[/TD]
[TD="align: right"]17.5[/TD]
[TD="align: right"]1.49[/TD]
[/TR]
[TR]
[TD]10L-101-1[/TD]
[TD="align: right"]15.0[/TD]
[TD="align: right"]1.24[/TD]
[/TR]
[TR]
[TD]10L-101-1[/TD]
[TD="align: right"]12.5[/TD]
[TD="align: right"]0.92[/TD]
[/TR]
[TR]
[TD]10L-101-1[/TD]
[TD="align: right"]10.0[/TD]
[TD="align: right"]0.63[/TD]
[/TR]
[TR]
[TD]10L-101-1[/TD]
[TD="align: right"]7.5[/TD]
[TD="align: right"]0.41[/TD]
[/TR]
[TR]
[TD]10L-101-1[/TD]
[TD="align: right"]5.0[/TD]
[TD="align: right"]0.24[/TD]
[/TR]
[TR]
[TD]10L-101-1[/TD]
[TD="align: right"]2.5[/TD]
[TD="align: right"]0.11[/TD]
[/TR]
[TR]
[TD]10L-101-1[/TD]
[TD="align: right"]0.0[/TD]
[TD="align: right"]0.00[/TD]
[/TR]
[TR]
[TD]10L-102-1[/TD]
[TD="align: right"]20.0[/TD]
[TD="align: right"]0.35[/TD]
[/TR]
[TR]
[TD]10L-102-1[/TD]
[TD="align: right"]17.5[/TD]
[TD="align: right"]0.30[/TD]
[/TR]
[TR]
[TD]10L-102-1[/TD]
[TD="align: right"]15.0[/TD]
[TD="align: right"]0.25[/TD]
[/TR]
[TR]
[TD]10L-102-1[/TD]
[TD="align: right"]12.5[/TD]
[TD="align: right"]0.23[/TD]
[/TR]
[TR]
[TD]10L-102-1[/TD]
[TD="align: right"]10.0[/TD]
[TD="align: right"]0.11[/TD]
[/TR]
[TR]
[TD]10L-102-1[/TD]
[TD="align: right"]7.5[/TD]
[TD="align: right"]0.07[/TD]
[/TR]
[TR]
[TD]10L-102-1[/TD]
[TD="align: right"]5.0[/TD]
[TD="align: right"]0.04[/TD]
[/TR]
[TR]
[TD]10L-102-1[/TD]
[TD="align: right"]2.5[/TD]
[TD="align: right"]0.01[/TD]
[/TR]
[TR]
[TD]10L-103-1[/TD]
[TD="align: right"]0.0[/TD]
[TD="align: right"]0.00[/TD]
[/TR]
[TR]
[TD]10L-103-1[/TD]
[TD="align: right"]20.0[/TD]
[TD="align: right"]1.75[/TD]
[/TR]
[TR]
[TD]10L-103-1[/TD]
[TD="align: right"]17.5[/TD]
[TD="align: right"]1.50[/TD]
[/TR]
[TR]
[TD]10L-103-1[/TD]
[TD="align: right"]15.0[/TD]
[TD="align: right"]1.27[/TD]
[/TR]
[TR]
[TD]10L-103-1[/TD]
[TD="align: right"]12.5[/TD]
[TD="align: right"]0.92[/TD]
[/TR]
[TR]
[TD]10L-103-1[/TD]
[TD="align: right"]10.0[/TD]
[TD="align: right"]0.62[/TD]
[/TR]
[TR]
[TD]10L-103-1[/TD]
[TD="align: right"]7.5[/TD]
[TD="align: right"]0.40[/TD]
[/TR]
[TR]
[TD]10L-103-1[/TD]
[TD="align: right"]5.0[/TD]
[TD="align: right"]0.23[/TD]
[/TR]
[TR]
[TD]10L-103-1[/TD]
[TD="align: right"]2.5[/TD]
[TD="align: right"]0.08[/TD]
[/TR]
[TR]
[TD]10L-103-1[/TD]
[TD="align: right"]0.0[/TD]
[TD="align: right"]0.00[/TD]
[/TR]
</tbody>[/TABLE]