Restriction on entering duplicate data already existing in an excel spreadsheet. ie. checking a spreadsheet for duplicates before accepting a lead.

Restriction on entering duplicate data already existing in an excel spreadsheet. ie. checking a spreadsheet for duplicates before accepting a lead.

I need to create a form that,

1. Does not allow a list of numbers to be entered. ('Does not equal' query is not possible since list is very long).

2. Gives a warning message whenever such number (existing in spreadsheet) is filled in a field.

3. Fails submission of form containing such number (existing in spreadsheet).

Is it possible to do in zoho forms?