High latency and jitter in Golden CO

Greetings,

For the past few weeks now we've been having issues with latency and jitter in Golden CO and it seems to be getting worse.  I manage the networks for 2 businesses in Golden, their owner in downtown Denver, and myself, also in Golden.   The jitter among the Golden locations and to our VoIP provider (Vitelity) in Englewood is at the point where even VoIP calls directly between the 2 Golden businesses is getting choppy.  

Between the 2 businesses...

ping -c 500 -s 270 -i 0.02 -q static.XXXXXXXXXX.com
PING static.XXXXXXXXXX.com (173.164.63.XX) 270(298) bytes of data.

--- static.XXXXXXXXXX.com ping statistics ---

500 packets transmitted, 500 received, 0% packet loss, time 11491ms
rtt min/avg/max/mdev = 17.144/35.905/131.760/20.825 ms, pipe 6

Between one of the businesses and Vitelity...

ping -c 500 -s 270 -i 0.02 -q outbound.vitelity.net
PING outbound.vitelity.net (64.2.142.214) 270(298) bytes of data.

--- outbound.vitelity.net ping statistics ---
500 packets transmitted, 500 received, 0% packet loss, time 11820ms
rtt min/avg/max/mdev = 24.916/45.499/151.143/24.411 ms, pipe 6

Contrast this from the owner's home in Denver to Vitelity...

ping -c 100 -s 270 -q -i 0.02 outbound.vitelity.net

PING outbound.vitelity.net (64.2.142.106) 270(298) bytes of data.

--- outbound.vitelity.net ping statistics ---
100 packets transmitted, 100 received, 0% packet loss, time 2040ms
rtt min/avg/max/mdev = 25.357/27.099/42.480/2.390 ms, pipe 2

Throughput does not seem to be affected and packet loss is nil.  Utilization was miniscule when I performed the tests and the routers and modems all seem to be operating without issues.  The latency itself isn't great but the jitter is killing us.

I can provide more details privately of course.  Trying to work through these kind of issues via phone has been problematic in the past so any help here would be appreciated.

thanks.