Complex context rules

[Steve Rickaby]

I am in the situation in which I want an element to be able to check whether its *parent* is the first element of *its* parent.

Put another way, element A needs to be able to check whether A's parent is the first element of A's grandparent.

The on-line struct dev guide (page 135 in FrameMaker 7 version) seems to imply that context rules of the form:

If context is: Parent {first} < GrandParent, or

If context is: Parent {after Grandparent} < * < SomeOtherAncestor

are valid, but I can't get these rule to trigger. Are there any pitfalls here?
-- 
Steve