Cannot send data with recording

We could not send (upload) finalized form with voice recording an entire interview with background audio recording, because the size seems too large for slow internet connection (at a rural town in Africa).
We use the minimum format of recording (voice-only).
I would like to send a form without recording file during the field survey and send data with recording file later after enumerators return to a large city. Is it possible?
Alternatively, can we record only a part of an interview (instead of the entire interview)? The survey takes about two hours but we need the voice-recording of only half of the interview.

@rbm, maybe you could keep collecting the data and then submit the entire data once the data collection is over (reaching back to town, where the internet is strong).

You are right. But the HQ needs to check the data every day in another place. It seems we cannot separate a voice file or cannot reduce the size of voice-recording in an interview.

Submitting only a portion is not possible.

OK. Thank you.