With your current design, the 6 emails are a moving train and you want to pause the train at certain points.
To implement this, you would need the primary campaign to stop everytime it sends a nurture email and wait until thats completed before sending the next one. So it might look like this:
Campaign A: when requested, request sub campaign to send next email in the nurture track.
Campaign B-G: when requested, check if lead is eligible to receive email. If eligible, send email, wait 1 week, then request Campaign A. If not eligible, wait 1 week and check again. Continue checking for 5 weeks or so (this will need to time out.)
You'll also need a campaign to stop the flows in Campaigns B-G when the emails are actually sent.