The elements in the interactive layers of the Timeline can be grouped in order to be moved at the same time.
To select and group some elements, use the multiple selection squares you'll find next to each layer name in the Timeline. Click on all the elements you'd like to group and the group will be automatically created. Once the group is created you can see and change its properties in the Properties panel. You can add and remove elements from the group and move all of them along the Timeline by adding or substracting as many minutes and secons as you want. You can also move all the elements by clicking and dragging the group in the Timeline.