Yes, this can be done, however it will also require a PBX software or hardware solution. IVM on its own is simply an automated answering/attendant system.
In order to add more complex call routing (e.g. call into IVM, select support and then ring the VoIP phone associated with support), then you need a Private Branch Exchange (PBX) system such as NCH's Axon software or Digium's Asterisk.
The way it works is, your PBX registers directly with your VoIP service. It will then be set to send incoming calls to the PBX extension linked to IVM. IVM answers the incoming call and based on the selected option will then transfer the call to either a particular extension or ring group (the PBX handles the transfer and sends the call to the appropriate destination). The ports on the modem will be linked to the PBX as individual phone extensions and can be configured to accomplish whatever you need in terms of inbound and outbound call routing.
It's not too complex to understand (at least I don't think). Most settings are clearly labelled and the help file usually provides a description. The basic steps are:
- Install IVM and Axon
- If IVM hasn't automatically done so (which it should do), set-up an extension for IVM
- Setup an external line in Axon that links to your VoIP account, set it to ring on IVM's extension
- Create/edit the extensions for your modem and setup your modem to link to those extensions using the username/password combination you set in Axon and the IP address of the computer for the server or proxy field.
Now all you have to do is set-up your call flow for IVM.
IVM has one of the easiest call flow designers around so it shouldn't be too hard. Simply create a new OGM for each 'prompt' you want (e.g. 'Press 1 for sales, 2 for support') and set each OGM to respond when certain keys are pressed, for example 1 may be set to transfer to an extension linked to your modem.