How to identify and filter out candidates who has recieved a correspondence?

Summary:

How to identify and filter out candidates who has recieved a correspondence?

Content (required):

I have a requirement to bulk send emails to about 500 candidates but system allows bulk email sending to only 150 candidates at one time. How to identify the candidates who has recieved email and filter out them while sending the next batch of emails as I don't want to send duplicate emails. Have you happen to come across similar situation and what was the approach, any suggestion would help me greatly.

Version (include the version you are using, if applicable):

21C

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