nixos-config/home-manager/i3/workspaces/workspace-2.json

// vim:ts=4:sw=4:et
{
    "layout": "tabbed",
    "type": "con",
    "nodes": [
        {
            "name": "Telegram",
            "swallows": [
               {
               "class": "^TelegramDesktop$"
               }
            ],
            "type": "con"
        },
        {
            "name": "Signal",
            "swallows": [
               {
               "class": "^Signal$"
               }
            ],
            "type": "con"
        },
        {
            "name": "Element",
            "swallows": [
               {
               "class": "^Element$"
               }
            ],
            "type": "con"
        },
        {
            "name": "Whatsapp",
            "swallows": [
               {
               "class": "^Whatsapp-for-linux$"
               }
            ],
            "type": "con"
        }
    ]
}

{
    "name": "Slack",
    "swallows": [
       {
       "class": "^Slack$"
       }
    ],
    "type": "con"
}