A Line Rig will connect all of your selected layers together into a straight line.
Then you can quickly & easily have the size of one layer affect the scale and position of its neighbours, creating a nice flexible line.
If a Line Rig is too 1-dimensional for you, try a Grid Rig!
Flex Grid Rigs will take your existing layouts and create horizontal and vertical controllers for them, letting you dynamically flex groups of layers as rows and columns.