I usually would recommend to us the External Channel like people do with Slack
With Cliq you can have group chats as well as external channels and I'm assuming it's the same with Slack.
The recommended approach by Zoho is to use group chats for ad-hoc conversations and to use channels for more permanent team communication.
I think support issues and customer conversation belongs to the one-on-one and group chats while long term project collaboration is best served by channels.
That's why I think most a lot of people can work fine without external channels. You don't get external channels in the free tier of Zoho Cliq.