When deploying the Exchange 2007 mailbox server role, you are given the possibility to implement high availability by using continuous replication. You can choose to deploy local continuous replication, clustered continuous replication, or standby continuous replication.
But is it possible to combine any of these types of continuous replication? Yes and no. You cannot enable local continuous replication on any storage group created on a mailbox server configured using clustered Continuous Replication. Neither is it possible to configure standby continuous replication and specify a target Exchange 2007 Sp1 Mailbox Server that has storage groups with local continuous replication enabled. But, it is possible to configure standby continuous replication for a storage group and specify a CCR passive node as its target.