Hello Dumlu,
yes you should be able to configure the channelized OC-3 with a level of detail of DS0 channel-group on an E1/T1.
( ech group made of one or more DS0 timeslots)
Be aware that:
the OC-3 will be carrying three DS3/E3 channelized on the port.
On their turn each channelized DS3/E3 can be configured as a group of T1/E1 ports.
Each E1/T1 can be then configured as a controller with one or more channel-groups.
The ability of using sub E1/T1 depends also on the capabilities of external RED /ADM connecting to the OC-3 port.
see
http://www.cisco.com/en/US/docs/interfaces_modules/shared_port_adapters/configuration/7600series/76cfstm1.html#wp1161296
However, you can expect that there will be a limit on the max number of channel-groups you can configure on it.
Hope to help
Giuseppe