staggered email send

I have working macro that sends emails to every address in a column. As the number has increasd to over 200, my ISP wants me to stagger the email send to 100 per hour.

Is there a sensible way of doing this? I can write a delay in the macro but things get complicated when pages are closed, data is changed etc during that time as it all feeds from the main Excel database which is not static, certainly not over the 3-4 hours I would need to stagger the email send?

I've tried to find out a way of staggering it in Outlook instead but no luck there either.

I've thought about loading all the addreses into an array at first rather than reading them as it progresses. The toruble with this is if the databse is closed during this process, I've no way of knowing which emails have been sent other than dumping a sent list each time, but this starts sounding really messy.

Thanks in advance