[lumost]

There is no restriction on relative velocities between objects from a given observer as long as all objects have velocities less than the speed of light. You can point laser pointers in opposite directions and the "front" of the laser pointer will recede at "2x" C from the opposite pointer.

In the case of the expanding universe, our standard "flat" space time represented by minkowski space is warped into de-sitter space. As distances increase apparent acceleration increases up to and beyond the speed of light due to the expansion of space time.