Implement a way to fix requesters emails in datasource

Hi,

I am wondering if its possible to implement something to allow requesters to select only specific requesters from the datasource.

As of right now, when people send us an email in freshservice for example their gmail, hotmail, etc, it create a requester.
We use 3 domains in our company: @example.ca, @example.org, @example.com (thats just an example)

I want to know if its possible to display only these 3 domains from the “all users” datasource so people can ONLY select these person from the datasource from a specific service catalog.

This will prevent people to select gmail email to select a company user which cause issues with workflows.
We have a workflow that check this selected user from ActiveDirectory, but gmail, hotmail, etc are not in our AD of course...

Thanks again for your time