All cells within a column must have the same width. However, you can use
"Merged Cells" to create the appearance of different width cells in a column.
Insert a new column adjacent to your existing column. Merge the cells of
this new column with your original column for each row that will NOT be a
special width. The remaining rows will now appear to have different widths
from the others in the column.
WARNING: Using merged cells can cause problems with formulas, sorting, and
copy/paste actions.
HTH,
Elkar