Binding SIP to multiple, but not all, IP addresses

Anyone know if it is possible and, if so, what the syntax is, to bind SIP to multiple but not all IP addresses?

in sip.conf [like iax.conf] the service gets bound to IP addresses with the line

bindaddr=x.x.x.x

If you put 0.0.0.0, it will bind to all addresses. In a HA Cluster, on the active node, if you have a box address of 192.168.1.101 and a floating address of 192.168.1.102, then if you use

bindaddr=0.0.0.0

you will find that phones on the 192.168.1.x subnet will not register on the floating address, which of course defeats the point of HA clustering. What happens is that the registration packets go to the floating address 192.168.1.102 but the response packets appear to come from 192.168.1.101 [same NIC but the packet contains the base address attached to the NIC], so the registration fails. The SIP and IAX stacks seem to be quite lame. You can solve this by changing the sip.conf and iax.conf bindings to

bindaddr = 192.168.1.102 ; the floating address.

This works just fine. Problem solved.

However, if you have 2 NICs, you can have two floating IP addresses, one on each. But how can you bind SIP & IAX to 2 NICs? Having tried

bindaddr = x.x.x.x , y.y.y.y

and

bindaddr =x.x.x.x
bindaddr =y.y.y.y

I have concluded that it cannot be done. Anyone know otherwise?