master.cf - multi IPv6 bindings but single IPv4 fallback in mixedmode possible??

[dravion.sm...@gmx.net]

Hi@ Developers

I have a setup in my master.cf for multiple IPv6 Addresses with SSL and 
TLS configured and on my IPv6 Layer everything works as expected.
The Problem: Some of the Mailhosters doenst accept IPv6 MTA's  at this 
time and so i need a fallback, but i have only 1 IPv4 Address in my Root 
Server Webhosting Package.

Can i run IPv4 Virtualhosts on one single IPv4 address at the same time 
while IPv6 instances are running normally side by side?

Right now i use a single IPv4 / virtual host smtp.mydomain.tld but 
unfortently in the rceived by header of Thunderbrid and other Mail 
clients there is
allways my IPv4 smtp forward mta embedded. Thadts not i what i want. I 
want for each domain a single ipv4 mta, running side by side with my 
working IPv6 Setup.

Dravion