Helping agile team with "out of team" work is always a challenge, they naturally tend to rely only on their own resources. It is really a tricky management problem, and I have had my fair share of failures around teams that do not know that they would be better off with help. Yet my current thinking is that it is possible to set up parallel intra-team processes, but for these to work they need to include a large amount of inquiry activity from the teams; By inquiry I mean that people have questions for which they want answers. So when team members have questions, and these do not find answers within the team, that is when supporting them with intra-team processes works.
In "out of the book" scrum, the product owner and the scrum of scrums are meant to be the "only" intra-team process. But the bigger the domain, the more both the product owner and the scrum of scrum become bottlenecks. Now the insight, is that you can add more interfaces into your teams but they must be PULL oriented: The team members must be asking for learning.
There is catch, like with any form "leveraging", any misalignment between what is learned and what you are trying to achieve is going to cause to harm. With scrum, it is then the job of the product owner to work with this external process and keep it aligned.