I would like to design a microscope objective(s) with a fixed parfocality and Back Focal Plane (BFP) with respect to a given surface.

For example:

Objective 1: parfocality Z mm, BFP position from vertex of last surface = BFP1 mm

Objective 2: parfocality Z mm, BFP position from vertex of last surface = BFP2 mm

1. How can I design these two objectives (in multi-configuration if necessary) such that I can optimize the designs around a given BFP position with respect to a coordinate surface (assume surface 0).
   1. For instance; the BFP position should be constrained to 3mm from Surface 0.
   2. What operands can be used to control the focal planes/focal lengths (rear and front) of a optical design in Zemax?
2. When designing multiple related optics - such as more than one objective lenses for a microscope which share common parameters. What is the best practice to control the common parameters such as parfocality and BFP position between these multiple objective designs?

Thanks