VIOS IP address - separate vlan for vios servers ?

Hello,

Lets say for simplicity that I do not use any vlan config inside my server - one lpar group use hea physical port1, another group hea physical port2. Physical port1 configured as vlan1 on external switch, physical port2 as vlan2.
What is the common practice - should I isolate my vios partitions and assign those to vlan3 for example ?

thanks
Vilius