Hershel,
That would work, but I agree with Dwayneg about using ARS instead of the actual trunk group. It is almost always the preferred way to allow for greater flexibility and control over your outbound calls and dialing strings.
So, set your Outgoing Extension to ARS, default 92000, and your Emergency Extension to 74001 so 911 calls use the Analog Trunks to dial out. Then make sure that your SIP Trunk Group is the only Trunk Group in your Numbering Plan Facility Groups that would be needed to call the associated devices number.
If you have ARS Only set up a COS for your phones you can either remove that or go to the Analog Trunk Group and set Exempt From ARS Only to Yes. Then you can either turn your system into a KSU and put the trunks as Individual Trunks on keys or just use the Trunk Group. If you go the KSU route then don't forget to change the Hold Button on the key maps to System Hold instead of Individual Hold.
Thanks,
TE