[Interspire] How to pause and resume sending using cron or some script

I am sending up emails through interspire setup on a VPS with exim+ip rotation. But my interspire setup sends emails through only one IP address to all the email list (don't rotate the IPs). But when I pause the campaign and resume it again then it sends email through other IP.

Also when I send test email to my gmail - it will always change the IP. So, my problem is that it sends with same IP for a campaign until it is paused or resume. How can I either automate this resume/pause say after every 15 minutes or what do I change in exim configuration to rotate IP automatically after fixed time. Thanks for any help

just change your cron entry for iem to only run when you want to send, easy peasy

I have edited the question with more details, any help please?

That's not related with cron I believe. You'll need to set virtual meta pool for your IPs. Are you sure you have already created one?