Unfortunately, I don't have Numbers. I use Excel. Furthermore, this answer is really more of a work-around than a straight solution to your question. With those stipulations, below is a work-around for an Excel user, but numbers probably has similar features.
When I select just column 2 (perhaps the Name column) and click the alphabetize button, Excel asks me to expand the selection or continue with the current selection. Although the default is "Expand the Selection", if you choose "Continue with Current Selection" instead it only alphabetizes the one column. So you could simply only select your second column (Name) to alphabetize and leave your first column (Entry Number) alone.
It sounds as though you will have more than 2 columns, however. For this situation, you could (assuming Numbers is similar to Excel in this way, too) select all columns except the first column and choose a "Custom Sort" choice (Excel's version). Then, you can set which column to sort by (perhaps column 2: Name). As long as you still select "Continue with Current Selection" just like above, the each row (one entry) will stay together but they will be sorted alphabetically according to the indicated column without changing the first column.