Complex call forwarding?
 

Preamble: I'm new to VoIP technology (and other telephony specs), but I do have a background in WAN IP routing architectures and protocols ...so I'm trying to learn.

Configuration: I have a PhonePower (SIP?) account with 5 DIDs connecting via Grandstream HT502 over Verizon DSL.

703-xxx-xxx0 = home phone (Virginia)
410-xxx-xxx0 = "virtual" (Maryland)
410-xxx-xxx1 = "virtual"
410-xxx-xxx2 = "virtual"
410-xxx-xxx3 = "virtual"

Senario: I want to receive prepaid collect calls from a 410-xxx-xxx? landline, to the 410-xxx-xxxx DIDs that then forward to various 703-xxx-xxxx cell phones cost effectively.

410-xxx-xxx0 -> home phone (done automatically by PhonePower)
410-xxx-xxx1 -> 703-xxx-xxx1 cell phone1
410-xxx-xxx2 -> 703-xxx-xxx2 cell phone2
410-xxx-xxx3 -> 703-xxx-xxx3 cell phone3

My logic: (Please help me learn, if I don't have this right)

1) Call originates from 410-xxx-xxx? PSTN
2) Destination 410-xxx-xxx1 is "registered" (somehow?) to PhonePower, so it gets "routed" to their PBX?
3) PhonePower PBX passes to their SIP server?
4) PhonePower SIP server "encapsulates" the call into a SIP URI?
5) Call is routed to 703-xxx-xxxx destination on IP network?

Challenge: Here's what I think needs to happen.

1) Inbound calls destined to the 410-xxx-xxxx DIDs need to be intercepted at the PSTN -> IP boundary, prior to reaching the PhonePower SIP server. Is this what Voxalot does?
2) Then they need to be forwarded/repointed to a different IP -> PSTN "termination" provider, that offers low Outbound calling rates.
Voxalot Call Connection?

Help Needed: How do I do that?

1) How do I setup Voxalot to "intercept" the calls? (I read all of the tutorials, but I'm a little lost in the terminology for some of the steps)
2) Where do I find an Outbound "termination" provider that will service my DIDs? (They all seem to provide service using their own DIDs)
3) Do I need to get more DIDs from the Outbound "termination" provider", and somehow "link" the 410-xxx-xxxx DIDs to the new local 703-xxx-xxxx DIDs?
4) Can I set up Voxalot to intercept and forward 410-xxx-xxxx DIDs to a termination provider's 703-xxx-xxxx DIDs, then configure those to forward to my PSTN cell phones?

Update: Now I've added a VoIP.ms account to forward to, but I can't figure out get calls to go through.