The CR200 series and CP900 series devices support multi-remote pairing.
This means that a single CP900 can be paired to any number of remotes (including any combination of CR230, CR220, CR210). Any of the remotes can be used to control the CP900 when in range, without requiring re-pairing.
Several remotes that are paired and in range may be used to control the CP900 simultaneously – i.e. it will respond to the sequence of commands it receives in order, regardless of which remotes were used.