The Blend component is very similar to the group component, it triggers all its child components at the same time but it doesn't appear on the mixer view. Also through its inspector UI it is possible to set the children volumes, saving time from having to go to each node.

Watch the following video explaining more about this Component

https://www.youtube.com/watch?v=h08OerVyIu0&index=5&list=PLjo4vf11pt-MWtpdnyJdqJ41khf4YhS8y