Transmit the same signal through both TX ports

[TheGribble]

I have a signal sampled at 61.44MHz, is there any way to transmit that exact same signal through both TX ports without running in to the USB speed limit? I'm getting this warning:

The total sample throughput for the 2 active channels, 122.88 Msps, is greater than the recommended maximum sample throughput, 80 Msps. You may experience dropped samples unless the sample rate is reduced, or some channels are deactivated.

I'm currently streaming using the BLADERF_TX_X1 format with a single buffer, and it kind of looks like it's working. Is this sending a single copy and transmitting it through both ports or is it duplicating it under the hood?