In reply to chr_sue:
Since I posted my question I came up with a solution that does not break the “monitor is for analysis only” mentality, which is to essentially create a second driver called “slave_driver”. This will listen to the bus and communicate with a slave sequence, which can then be used to driver other sequences on a different bus. The original driver is then (preferably) renamed “master_driver”.
Therefore there are now two sequencers created in the agent of the same type, one for master transactions and one for slave transactions. The master can be disabled in passive mode, and another bit can be used in configuration to enable or disable the slave driver.
Let me know what you think of this approach. It seemed preferable to me, since it draws from the same thinking behind the example described in Sequences/Slave