Both Uses

contingent
in
A Spool of Blue Thread
(Edited)

This agreement is contingent upon his mother's promise that she will never, ever, for any reason, reveal her identity to her son unless and until she assumes permanent responsibility for him; nor will I reveal it myself.
p. 177.4 *

contingent = dependent upon
The Bouton Road contingent was eating supper at her house, now that their pots and dishes were packed, and she had just set a pork roast in front of Amanda's Hugh for carving.
p. 343.1 *

contingent = group

Definitions:

(1) (contingent as in: contingent upon)
to be determined by conditions or circumstances not yet established
(2) (contingent as in: the Canadian contingent)
a sub-group united by something in common
in various senses, including:
- a squad of soldiers sent to do a job
- members of an association at a convention of many associations
- all the women at a meeting with women and men
(3) (meaning too rare to warrant focus)