You can remove sorting by specific columns except for sorting by the columns the records are grouped by. These sorting levels can be cancelled by ungrouping records.
To remove sorting:
Right-click anywhere in the grid and choose Sort > Sort by Form from the pop-up menu. The Customize View window opens on its Sorting tab.
In the Sort by These Fields pane,
double-click the field corresponding to the sorting level to remove. Repeat this step for each sorting level you want to remove.