Separate thousands of emails into 1000 group.

I currently receive clients through a list with their first, last name and also their email. However there are sometimes over 10,000 emails.
I would like to push a button that selects exactly 1000 emails. Push button again, another set of 1000 emails that can be selected/copied and put into my email client.
Not sure if there is a formula out there, or if I have to write a macro for this function to happen.
Any help would be appreciated.

Thank you in advance!

Sequential Would be great, that way the same email isnt used twice.

Thank You! Worked beautifully! If I have questions, I will let you know.