Yes, you can show the top 20 entries in a pivot table and group the remaining entries as 'Other'. Here's how you can do it:

1. Create a pivot table with the data you want to analyze.
2. Drag the field that you want to show the top 20 entries for into the Rows or Columns area of the pivot table.
3. Right-click on one of the entries in the field and select 'Filter' 'Top 10' (or 'Top 20' depending on how many entries you want to show).
4. In the 'Top 10 AutoFilter' dialog box, select the 'Top' tab and enter the number of entries you want to show (e.g. 20).
5. Click 'OK' to apply the filter and show only the top 20 entries.
6. Right-click on one of the entries in the field again and select 'Group'.
7. In the 'Grouping' dialog box, enter 'Other' as the name for the new group.
8. Select the entries that you want to group together (i.e. all the entries that are not in the top 20).
9. Click 'OK' to group the entries together as 'Other'.
10. Your pivot table should now show the top 20 entries and a group called 'Other' that contains all the remaining entries.

That's it! You have successfully shown the top 20 entries in a pivot table and grouped the remaining entries as 'Other'.