[Dnsmasq-discuss] How to reserve 2 IPv6 addresses for the same host?

[Steve]

For years now I have been assigning both v4 and v6 addresses to my hosts 
this way

dhcp-host=dmz,F0:4D:A2:2E:AB:C4,server-d,       192.168.2.2
dhcp-host=dmz,00:11:0A:5F:F7:FE,pihole,         192.168.2.3

and

dhcp-host=id:00:02:00:00:AB:11:51:D7:96:BA:E4:CE:13:F5, 
server-d,      [fdfc:5b34:b12::2]
dhcp-host=id:00:02:00:00:ab:11:e5:57:e9:1f:92:75:89:50, 
pihole,        [fdfc:5b34:b12::3]

The hardware that Pi-hole was running on has died and I've installed the 
Pi-hole package on the server-d hardware and added a NIC so I can have 
separate addresses for the package. The v4 assignments work as expected.

The problem, of course, is that server-d has only the single DUID, as 
shown above, and I seemingly have no way to assign the 
[fdfc:5b34:b12::3] address to the new NIC. I've searched high and low 
for either a way to assign a separate DUID to the new NIC or for a 
different way (other than DUID) to identify the NICs. I've found many 
posts, going back over 5 years, on vaguely-related topics but nothing to 
address my need specifically.

If there is a way to accomplish my need/want I hope the answer is 
forthcoming here.

Thanks for your time.