Maybe create a first simulation for the 2 corners (just pin the rest of the plane) and apply the simulation as shapekeys, keyframe the shapekeys:
Then create a second simulation and in the Cache make it start when it is supposed to:
Maybe create a first simulation for the 2 corners (just pin the rest of the plane) and apply the simulation as shapekeys, keyframe the shapekeys:
Then create a second simulation and in the Cache make it start when it is supposed to: