using a custom property as a sort key ?

[Christopher Mitchell]

Howdy,

Is it possible to use a custom property as a sort key?  I have a stack 
of flashcards that have an embedded "permanent" order in the form of a 
custom property called Index.  I use a pretty crude script to flip 
through all the cards (after being shuffled, aka sort on key random), 
find the one with index 1, go to it, then sort on it.

Is it possible to say something like:   go to card with Index of 1

? (obviously that is not appropriate transcript, as i'm searching for 
the syntax)... this would be similar to saying something along the 
lines of     go to card with short name "xyz"

Surely this is implemented, and I just can't find it.

Yours,
Chris