expedient--Sister Jen and Todd

ex·pe·di·ent  (k-spd-nt)

adj.

1. Appropriate to a purpose.

2.

a. Serving to promote one's interest: was merciful only when mercy was expedient.

b. Based on or marked by a concern for self-interest rather than principle; self-interested.

3. Obsolete Speedy; expeditious.

n.

1. Something that is a means to an end.

2. Something contrived or used to meet an urgent need. See Synonyms at makeshift.

Context:
Sister Jen and Todd invited Ranger into the family photograph only when it was expedient, but Rosie was never in the photograph for any reason.