Import delay to avoid spam-response

We host our WP on a provider that does not like mass emails to be sent and may block the site, e.g. when sending 100 emails in 5 minutes.

Is there a way to import (email send for activation on for user) in small batches of 10 and 10 minutes steps, as an example?

Would this not be a good idea?

Alternatively, I would need to create 15 csv files and do the delay manually.

thanks

Carsten