Multi-Segment Feature Control Frame
You can add segments to GD&T symbols in much the same way as they are initially created. This creates an FCF stack.
Instead of selecting geometry, you select the Characteristic Symbol of an existing GD&T symbol.
Based on which Characteristic symbol you wish to add, the system will limit which existing symbols are available.
For example, adding Concentricity to the position tolerance of a hole is invalid.
FCF stacks are sorted by tolerance value. The largest value is always in the first FCF and the values decrease as you go down the stack.