In piecewise notation (real math symbol), how I could add more cases?

I wish to manipulate the expression R*D^2 / ( R*D^2 + s*L + s^2*R*L*C ) in the way it will show as: 1 / ( 1 + s*L/(R*D^2) + s^2*L*C/D^2)

There are some function in maple that I could use?

I ever find to much hard make expression look as i want. In my view, one of the greats problems in maple.

Thanks