This is actually not accurate. These changes RoChess is refering to are already implemented but they are in the Moving Pictures 1.1 code base. Basically this means they will not be included in 1.0.5 (also known as 1.0 Final). To give you a little insight into our development process, when we release the first version of a new major release, we split our code into two branches. The first branch is for bug fixes of the major release, and this is where 1.0.1-.1.0.4 has come from. The idea is to increase the stability of the software most users are using. The other "branch" of our code is meant for our next major release, and this is where enhancements to the program go.The problem is that you need to wait for v1.0.5 (the upcoming stable release) to become available.
StreamedMP already has support as well, just make sure to get their latest version.
Holzi, you can enable grouping from the MovingPictures configuration in Advanced Settings.