How can I store multiple channels with the same frequency in channel database?

My university dormitory offers QAM digital cable service, to which I have a USB TV tuner connected via a coaxial cable. Kaffeine has no trouble detecting this device (Hauppauge WinTV-PVR-950Q), and is able to detect every channel offered, using the us-Cable-Standard-center-frequencies-QAM256 scan source.

However, when I attempt to save the channel list, it only retains one channel per frequency. Although this is not an issue for most cable channels, fifteen of the local over-the-air ATSC channels are carried by the cable system using just five frequencies, and if I attempt to add each of these channels individually, the last one selected overwrites the previous entry.

Is there a way to modify the channel database manually to include the extra channels?

I am using Kaffeine 1.2.2-2 on Ubuntu 14.04.2 LTS.