Sort column, new sort after each blank cell

I have a column of numbers which has blank cells throughout. How might I sort the column and after each blank cell sort the next range of cells again in order, keeping the blank cells in place. Example below
Old New
1 1
6 2
3 3
2 6

2 1
5 1
1 2
1 4
4 5

9 1
3 2
8 3
1 7
7 8
2 9

Many thanks

Introduce a helper column (column B) and insert a blank row 1 above your data. Put zero in cell B1 and this formula in B2:

=IF(A2="",MAX(B$1:B1)+1,B1)

Copy this down to the bottom of your data. Then select the data in columns A and B, from row 2 onwards, and apply your sort, choosing column B as the first sort key, then column A.

You can remove column B afterwards if you don't need it.

Hope this helps.

Pete