Is there a simple way to convert a contact to pipeline based on email receipt? Email-in doesn't look like the answer.

Is there a simple way to convert a contact to pipeline based on email receipt? Email-in doesn't look like the answer.

First, let me say, I think I made a mistake choosing Bigin over CRM and now I'm trying to do something in Bigin I don't think it was designed to do, which is manage leads. It's either contacts or Pipelines, no lead nurturing in between. So now I'm looking for workarounds to make staying in Bigin work for us because I already tried the CRM and ran into a database entanglement that forced us into Bigin. But I won't go into that now. Just felt the need to say this so that answers you give won't be, "you should be in the CRM instead." ;)

Here's what I want to do: assign a contact who replied back to a mass email to a pipeline if they reply back. 

Bigin support suggests I try Email-in. Here is my reply to that: 

I just looked into Email-in and I can't see how this is helpful at all but only because Zoho left out important functionality - unless I'm wrong. I'll explain and then you can let me know if I'm missing something.

First, the only way I can use the alias is by making it public and I don't want to do that because then we'll get spammed and our pipelines will fill up with spam. 

But if I could choose it as the reply to in the mass email, then that would be great. Unfortunately, I don't see that option when I create a mass email. 

And then I thought, what if I added it as an organizational email. Then I can add it as a reply-to. Of course that doesn't work because you have to confirm the email, and unfortunately that is not possible either.  I tried that thinking it might go to the main email. I got none. Which leaves me with this question: What good is an alias if it's not an alias? I see nothing in the settings that tell you who the email should be forwarded to, so apparently it's not really an alias. It's just an email that lets Bigin know it needs to do something with it. But then that means, if you give out that email so emails to it will go into pipelines, then who is going to get the email? No one??? 

Then I thought, what if I add it as another reply-to email address. The problem is there can only be one. 

So I'm stuck. 

Ok, all that sounds really stupid to me, so stupid, in fact, that I'm sure I must be missing something. What is it? 

Is Email-in a solution? It seems useless to me. Or is there another way to accomplish this. 

As it stands, if we get a reply to an email, we have to manually turn them into a pipeline.  Doable, but a little more work. The bigger problem is the system is not set up for lead nurturing and my only hope is to find workarounds around this lack of functionality in Bigin. 

Am I right about any of this? Surely I must be missing something.