Can I pass a GROUP BY to an API call?
I think this makes sense as an addition - but note that there are 3 types of get api

1) api layer api - e.g anything that uses basic_get
2) query object api (contact, contribute etc)
3) random assorted api

1 is easy &amp; in one place - 2 &amp; 3 are ... not

BUT #1 changes substantially in 4.7 compared to 4.6 so you would need to fix at minimum in 4.7 &amp; add unit tests and ALSO in 4.6 if you want it to work there too.

(We are open to backporting the 4.7 internals en masse to 4.6 with an self-deprecating opt-in -eg. $params['options']['4.7plusmode'] = TRUE;
- the 4.7 code also supports custom field filters (e.g on address) and lays the groundwork for more nuanced acls since it permits joins in simple api which is a blocker in 4.6)