asterisk users - Jan 2009 - is multiple contexts in alsa.conf possible

Is it possible ot have multiple contexts in alsa.conf

[general]
autoanswer=yes
input_device=hw:0,0
output_device=hw:0,0

[usbaudio]
autoanswer=yes
input_device=hw:1,0
output_device=hw:1,0


is Dial(Console/usbaudio) valid?
I presume Dial(Console/dsp) uses the default or general context above.

how do you direct a call to the second ALSA device usbaudio?

Thanks,

jerry