In my Fortune 500 employer, we have pan-regional task forces/committees people can join for collaboration like this. I'm on the Engineering Training Taskforce

In my Fortune 500 employer, we have pan-regional task forces/committees people can join for collaboration like this. I'm on the Engineering Training Taskforce in my region. We meet an hour a month to plan various events, including "Tech movie nights". Pre-COVID we'd get upper management to approve a small budget for popcorn during movie showings, etc. We also have a few (infrequent) long-running series of invited talks on a theme. Follow-up discussion from earlier in a series is good, but you need it to not interfere with people being able to selectively attend events. Presumably, you'd want to budget some time after the video screening to discuss the just watched movie, followed by some budgeted time for discussing the previous video. If you start out with discussion of the previous video, you're going to scare off newcomers. Or, you have a Slack channel (or similar) for the series and have drawn out asynchronous discussion. At least until you have critical mass, you need your series to be like an easy-watching low-context series with relatively self-contained episodes. Think The Simpsons instead of something that really requires investment to keep up with the context, like Game of Thrones. Being on a taskforce/committee does take extra time and effort, but does show initiative and can get one valuable exposure/mindshare from upper management. At least in our organization, cross-team collaboration looks good at annual review time.