AH - that explains your other thread as well. So the trouble is that ideally you would send the confirmation from a form processing step, which would send it to all registrants regardless or source, but you can't for reasons discussed in the other thread. So instead you have to send form submitters to a short wait step and then send the confirmation. You could do that with a decision rule as Peter suggested, but then that doesn't catch the external registrants (not in the invite segment). You could insert the external registrants using another segment, but then that's only evaluated every hour and the confirmation email for those folks is really slow. For that matter, evaluating the decision rule that checks shared list membership will be slow too - so they won't get their confirmation for another hour or so, which is way too slow.
So your idea was to insert the external registrants directly as a form processing step, which would immediately put them into the short wait step and then send them the confirmation. This works for the external registrants, because they were not already members of the campaign, but the invite recipients will be stuck on whatever step they were in when they submitted the form.
You could do it with two campaigns, one for the invite and the other for the followup, but you're trying to do it with one. So you're looking for a form processing step that would allow time for data processing before sending the confirmation, but not much time (a minute or so), and would work for both classes of contacts.
That is a very tricky set of requirements and I can't think of anything off the top of my head. I'll let you know if something occurs to me.
In my opinion the real problem here is the processing that has to take place before the confirmation can be sent. I would approach the problem as "how can we send the confirmation email immediately without waiting for processing" rather than "how can we delay the confirmation email a bit." If you don't mind sharing, what has to happen before the confirmation can be sent?
If it's what I suspect it is, I might have an idea how to work around it.
