export of a groupby element/list with a condition IF to an excel sheet

I would like to check a "worksheet" if it contains more than e.g. 250 entries if it does I would create a new excel-sheet and save it in a new file.

For example:

Zip code region:   Entries:
--------------------------

74...               400
73...               200   
72...                50

I used this command to get the number of entries I want to group:

worksheet['Zip-code-region'].value_counts()

Which way do I have to choose to make that? Do i have to create a list? or could I use a command with a for-loop?

thanks for help!