Hi Adrian,
Yes, this is absolutely possible. And the interpolation filters can be bypassed as well. You'll need to use "Dual SYNC Sources Mode" to achieve precise synchronization between parts. If you only need 4 outputs than the quad DAC3484 may be sufficient. Since you have independent signals, the isolation between channels may be a concern. In that case two DAC3482's may be a better choice.
The app note below talks about synchronization of the DAC348x family.
http://www.ti.com/lit/pdf/slaa584
Regards,
Matt Guibord