My wife is an artist and has about 700 (opt in) people on her mailing list. My provider has a limit of 100 addresses per email and 500 addresses per hour for spam control. We send a group email less than once a month so don't want to use an email marketer. I run Thunderbird. Is there any solution either in or outside of Thunderbird that will allow me to have a single group list and time the release of emails to conform to the providers restrictions. Right now I limit each list to <100 and send each list manually, holding the last 2 lists for an hour before sending.