Getting all Hosts(ip addresses) under a big group that has other groups inside it

[Network_Engine2]

Hi, 

I am using R80.10, and need some help regarding getting ip addresses under a big group.

Lets say i have a big group that has few groups under it, and then those groups have other groups inside them, and so on and so on until i reach the objects (servers,computers, etc).

i want to get to a situation that i have all ip addresses that are under the big group.

Does anyone know/ or did do such thing in the past?

Maybe some way in the API or SQL query through posgresql?

Thank you