Sub-teams communicating status at staff meeting

Questions

I am thinking about having each the three teams under me do a 3 minute update to the rest of the team at each staff meeting.  Any pitfalls with doing this?  Anyone else doing this another way or this way?  Or would having each team do a longer update but every 3 weeks be better?  (I didn't like this because it means less practice.)

My goals are:

1. Sharing what is going on between three teams that have some common touch points but are working pretty independently.
2. To have everyone on the teams practice doing a time boxed update to each other.  I'd tell them that they can do it any way they want and tell anything they feel is important.  There are 4-5 people per team so they'll get lots of practice.
3. Having the teams think about what they need to share - not just me.

As some background, my staff was put together a few months back from different groups that didn't know each other.  We've got 3 scrum teams that are working on different products but can share some ideas or technologies. 

Another data point is that we recently had everyone in the organization give 3 minute demos of their work - and pretty much everyone stunk at it!  We'll be doing that every 6 months and I want them to get better at it!

The final point is that they've commented that they don't know much about some of the other teams and I've tried to bridge the gap and poke them to ask each other.  But I finally :^( realized that I have to do more (or actually I do less and they do more)!

Does this seem like it will work?  The other managers here don't have the same issues with a new team.  They all thought the same about the demos but had no ideas.