[Asterisk-Users] Dual PRI fail over

[Tom]

I currently have a single PRI however we are getting a second PRI, and the
provider (qwest) wants to know if our PBX supports GSAS (they say its a
redundant d-channel technology but searching on google for GSAS reveals less
than nothing).  I've set something similar up before on a cisco 5350, where if
one of the PRIs fails, all of the calls destined for either PRI will be routed
down the one that didn't fail.  Basically the 2 PRIs are bonded together, and
act as one.  During normal operation the calls come down each PRI in a load
balanced fashion (IE if I've got 30 calls up, 15 will be on one PRI and 15 on
the other).

Is there any way to set something similar to this up in Asterisk?
Tom