I wonder if this is possible:
Using a Vega digital gateway (200G or 400G) behind a NAT router with two WAN sources and registering two SIP trunks to two external IP addresses?
So I would have two SIP trunks to two different SIP providers.
Are those gateways running Asterisk?
If so I would assume above scenario would not work, as Asterisk only knows about one external IP address, which it puts in the SIP headers when communicating with an SIP endpoint outside NAT.