Hoping that I am understanding your problem correctly:
What you want is configureable actually quite easily depending on the restrictions that your host has. And individual SSL's & dedicated IP's costing what they do, if your hosting Co. will not support this, time to look for a new host.
This assumes that your host supports and allows 'add-on domains', you have a dedicated IP associated with the primary account url, a SSL registered to the Primary account, reasonable MySQL DB cost or included, and other domain names FQDN's to add. cPanelX makes this easy to manage but is not required.
add your additional domains
set your SSL to function like a shared SSL that many hosts can/will provide.
Link/Set your Zencart to point to the correct URL for the SSL sessions in configure.php
Example:
Primary account = ABC.com
1st add account = ABCpots.com
2nd add account = ABCpans.com
3rd add account = ABCspoons.com
and so forth, The url names are inconsequential but the browser will indicate the HTPPS://www.name.com and one might like to keep it associated with your mini-store url's or the other way around; keep your mini stores url's associated with your primary url as this just appears more professional.
But it will work no matter the url name, just as the shared SSL also works but does not portray any linkage to the stores url at all.
Your primary url will process all the purchases and be setup with a single merchant/gateway account. This might not provide which store the purchase was made from, but this is available in each Zencart install.
Each added domain is addressable via its' own url and you have an instance of ZenCart installed for each in its' own space.