Control > Link/Unlink
[o]
Applies a hierarchical (parent/child) grouping to objects so that they
operate together but can retain their individual rotation and scale
values. If a link has already been established, this tool breaks the
hierarchical grouping of objects so that they operate independently
once again. 1. Select the object(s) to be linked. 2. Command Shift +
select the target object. This object should be highlighted in green.
If it isn't, deselect everything and go to step 1. 3. Click Control
in the main tool palette. 4. Click Link/Unlink in the lower tool palette.
5. To Unlink, hold option down click Link/Unlink in the lower tool palette.

Link Options Options:
Scale
- Inherit scaling factors from parent.
Rotation - Inherit rotational factors
from parent.
Position - Inherit x, y, and z offset
from parent.
Texture - Inherit all shader parameters
from parent.
Lattice - Inherit lattice deformations
from parent. (If the parent is linked to a lattice).
Boolean - Sets whether or not this
object will effect its parent at rendering time.
Union - Renders the parent and child
objects as though they were one.
Intersection - Renders only the
overlapping portions of the parent and child.
Difference - Carves out or subtracts
the child from the parent when rendering.
Smooth Seams - Enables Fusion»,
Pixels proprietary seam smoothing technology, hiding the visible ridges
created when non-continuous surfaces intersect.
Range - Sets the size of the Fusion»
blending.
Intersections - Intersecting objects
are smoothed. When this is active, the Range parameter is assumed to
be in world space.
Edges - The edges of the smoothed
objects are blended into the parent object. When this is active, the
Range parameter is assumed to be in st (parameter) space.