Hi Zaheer,
Yes, Axon can route multiple DID lines from different VoIP providers to the same extension. You configure one external line for each DID and have each line ringing to any group or extension. If you have a multi-line soft phone or IP phone you could have separate lines on the phone configured to a different extension, where each VoIP account goes to a different extension. Same phone but you know which account the call is coming in on...
Call routing - depends on what you mean by automatic...Axon allows for dialing rules that can be setup specifically to use a particular external line. But the rule digits must preface the phone number. For example dial 1+number to use voipstunt line, 2+number to use callcentric, etc. So not really least cost routing in the true sense, but similar manual functionality if you program your dialing rules for it...
Hope this helps. Also Axon is available fully functioned as a 14-day free trial, and allows for an InPhonex trial DID and account if you select the option.
DJ