[nsd-users] how to config one nsd zone as both master & slave using two interfaces -- one IPv4 & one IPv6?

[pgngw+dev001+nsd-users at f-m.fm]

i've built

	NSD version 3.2.7, r3084

from src on linux.

my test zone is config'd to slave IXFR from an offsite primary @
SERVER_A.

the same zone is also config'd to serve as master to nameserver @
SERVER_B.

in an all IPv4 scenario, where the single zone's one
"outgoing-interface:" specification (in IPv4) serves to BOTH request
IXFR and send NOTIFY, all's well.

i'd like to switch to IXFR from my offsite primary over IPv6 to
SERVER_A, but keep NOTIFY to SERVER_B over the IPv4 address.

But, iiuc, "outgoing-interface:" can't handle two different addresses,
and a single zone can't have two outgoing-interface specs.

how can I split the single zone's master & slave communications across
two IP protocols & interfaces?

do I have to set up 2 zones for this?

thanks!