How to add Gateway on eth0 to elastix?

Question

webmin

Good day!
There is Elastix with two interfaces:
eth0 - 192.168.0.7
eth1 - looks at the Internet
In the elastic web interface, you can set only 1 gateway, but I need one for each interface. When I change the gateway in the webmord, I start to see the server from another network 192.168.96.0/20, but naturally the sip stops working because of this :(
Webmin is screwed into this elastic, but I don’t know the password, I can’t reset it because there is no changepass.pl file