topology : two guest connected to physical LAN (vlan 620 and vlan 621)

on host :

1) creating bridge br0

2) creating bridge for guest 1 and guest 2 - to separate traffic

3) virtual network1 : I have default NAT 192.168.122.x DHCP feeding IP to eth1

4) virtual network2 : I want to use 192.168.0.0 for eth0

my question is what would be my virtual network2 looks like :

following is default xml :

<network>
<name>default</name>
<uuid>8778244b-1a0c-c15f-c348-26462a07a639</uuid>
<forward mode='nat'/>
<bridge name='virbr0' stp='on' delay='0' />
<mac address='52:54:00:3E:19:B3'/>
<ip address='192.168.122.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.122.2' end='192.168.122.254' />
    </dhcp>
</ip>
</network>

in virtmanager I assign this default to NIC1 and gets IP in range 192.168.122.x

I want to define another network and assign to NIC2 so I can get IP in range 192.168.0.x

my guest are on interface em2.620, em2.621 etc

thanks