Adding metadata to Listings/Mappings

[rohan-datar]

I am looking for a method of adding metadata to Listings so that I can pull out certain members in some situations, but otherwise treat all the members of the Listing the same, I thought the way to do that was with annotations, like this

ips = new Listing {
    "192.168.1.1"
    @Public
    "1.1.1.1"
    "10.10.10.10"
}

and then use reflection to check the members when I needed to, but just treat it like a regular listing otherwise.
But this results in a syntax error. Is there a way to make this work? Is there anther method to achieve what I need here?