You can create additional CANTalons and slave them to the CANTalons that you hooked up to your Robot Drive.
I put together a quick example here...
https://github.com/ozrien/FRC-Exampl...bot/Robot.java
More info in Section 9.1 of the Talon SRX Software Reference Manual to learn more about the Slave/Follower features in the Talon SRX.