"SiteSettingsA": {
    "DefaultUserPicture": "http://site.com/users/defaultavatar.png"
},
"SiteSettingsB": {
    "DefaultUserPicture": "http://site.com/users/defaultavatar2.png"
}

public class SiteSettings
{
    public string DefaultUserPicture { get; set; }
}

services.Configure<SiteSettings>("FirstSettings", Configuration.GetSection("SiteSettingsA"));
services.Configure<SiteSettings>("SecondSettings", Configuration.GetSection("SiteSettingsB"));

private readonly SiteSettings _firstSiteSettings;
private readonly SiteSettings _secondSiteSettings;

public HomeController(IOptionsSnapshot<SiteSettings> siteSettings)
{
    _firstSiteSettings = siteSettings.Get("FirstSettings");
    _secondSiteSettings = siteSettings.Get("SecondSettings");
}