Good morning,
Our company transitioned to Scrum last year. This year we brought on a new client that is also doing Agile and Scrum. Their project manager keeps trying to bake us into a single scrum team by attempting to schedule scrum ceremonies between our teams (daily stand-up, retro, backlog refinements, even sprint planning to ensure our internal sprints lineup with their sprints, etc). However;
⁍ We do not share each others backlogs. We maintain our own internal ticketing systems as well as work on our own servers.