clocking question

[iptuser]

If I have a Telco connection then I clock of the Telco/CO

network-clock- participate slot x
network-clock-select 1 T1 x/y

Controller x/y
clock source line

controller a/b
clock source internal

if I have a Telco/CO connection and a link to a PABX then again I clock off the Telco and extend the clock to the PABX by clock source internal by

controller s/r
clock source line

What happens if there is no Telco/CO connection. The GW is acting as a tandem device between a call manager across a link and a pabx but a link to another PABX which is being set up as a user. Can I configure the GW to be clock source internal for the T1 lInk to the PABX- there is no Telco/CO clocking from the Call Manager

network-clock- participate slot x
network-clock-select 1 T1 x/y


Controller e1 x/y
clock source internal