Hey there,
This is a public Team-Fortress-2-Group for soldier-specificated players. That's what it is in a nutshell.

If you want to get one step further, you can call this a center for community-acticity, like a little fun-fight on a random server on a specific time.
You can expect a community-play in Team Fortress 2 at least once a month.
In this group, we're helping each other in the way of trading, gameplay-tips, general questions to Team Fortress 2 etc.

Since this is not a clan in itself, more like a community / center for soldiers, its not required to use the [RAB] Tag, it's only for decoration purpose. Also, feel free to invite some of your friends that may like the soldier, always supports this group.