Hello,
In our version it is supposed to be able to move between teams. There is a patch that adjusts splash damage that changes this. I will look into this for you and get back to you.
Thanks!

OK, we've done some testing on this, and it seems the way it now works is as follows:

Splash damage CAN cross between teams, however the only border that seems to allow it is the border between the bottom and middle lineup. The border between the middle and top team will not allow splash damage.

In the first screenshot, targeting the bottom kakashi team (top kakashi of four) you can see Tsunade getting 7 damage messages, meaning she's splashing the middle kakashi team as well. In the second screenshot there are only three damage messages, meaning she's only splashing the middle team.

I tested this with Edo Fu, as well, and it seems consistent that the bottom border is permeable both ways but the top border is not.

As far as I'm aware, this version.
It was the opinion of some other moderators that this was put in place to prevent splashing in Decisive Bonds.

>When 6P and Izanagi Danzo get BT, I assume it will work same way, (well, for Danzo 1 grid only).

Probably.

> Thank you for your effort and help. :)

No problem!