I suggest you investigate using a mailing service, such as Mailchimp (although there are others as well). Some are free for a limited number of customers. Mailchimp, as I recall, allows up to 2,000 messages per month free. The advantage of a mailing service is that your messages do not get flagged as spam, and you don't have the many delivery problems. This can also let you develop a professional template for your announcements. On your question, no email client will ever be able to do that. That is because email clients are not designed for mass communications.