Hi there! Cat here from the Front support team 

Would you mind providing a bit more detail about the workflow you want to set up? Typically, a conversation becomes shared across multiple inboxes when smart-merge steps in to reduce duplicates where an identical conversation exists in multiple inboxes: https://help.front.com/en/articles/2238

It can also occur if the channel from another inbox is added as a recipient/sender on a conversation which was previously active in another inbox, however as far as I know, this is rarely done intentionally!

Normally if your team need to collaborate on a particular conversation you would use the comments section of the conversation to @mention other teammates to discuss the next steps. Another option is to create a Linked Conversation - this would create a new conversation which you can locate elsewhere but which would retain a link to the original. The last option I can think of off the top of my head is to use Discussions - you can embed references to conversations by including the conversation ID in a comment.

If none of these options sound suitable, please let us know and we’ll look into other options!

Cheers,
Cat