Peer groups and peers are siblings

[adrian62]

How could one separate peer groups from peers in a config section where they are similarly declared (neighbor ...) and at the same level of the hierarchy.
With a parser configuration like the Cisco_ios the peer groups and the actual member neighbors appear as siblings.
However it would be nicer if the peer group can be a container for the peer-group settings and children for each member peer.
This sample config:

router bgp 100
 router-id 0.0.1.1
 neighbor IBGP peer group
 neighbor IBGP remote-as 64500
 neighbor 172.16.255.12 peer group IBGP
 neighbor 172.16.255.12 description GW2

Decodes as:

{
    "bgp": {
        "local_as": "100",
        "router_id": "0.0.1.1",
        "neighbor": {
            "peer_group": "IBGP",
            "IBGP": {
                "remote_as": "64500"
            },
            "172.16.255.12": {
                "peer_group": "IBGP",
                "description": "GW2"
            }
        }
    }
}

The peer group is at the same level as the neighbor --which is how the config represents it. The peer group name (alpha string) can be matched by a separate rule but is it possible to write rules that would place peers into the peer group containers.

thank you