I have another idea that might be one of the many choices to consider. Mysipswitch currently supports a simple inbound routing rule by adding different prefixes to the Mysipswitch username. Example,
exten = work.Mysipswitch_username,1,Switch(Mysipswitch_use rname@local&cell@provider1&office@provider2)
exten = offwork.Mysipswitch_username,1,Switch(Mysipswitch_ username@local&cell@provider1)
where Mysipswitch_username@local will ring the device registered to Mysipswitch.
In Voxalot account, you can set up different rules where the destination
SIP URI's would be
work.Mysipswitch_username@sip.mysipswitch.com or
offwork.Mysipswitch_username@sip.mysipswitch.com or
anything.Mysipswitch_username@sip.mysipswitch.com that you defined in your Mysipswitch dial plan.