Blocking messages in one direction on a CAN bus
But I also have to send out messages on the same bus, but the vehicle may not receive these messages.


This is not possible.

You can be a silent node. That cannot transmit or acknowledge.
But you cannot transmit selectively. That is not how CAN bus was designed.

You can also be a hardware silent node by disconnecting can tx on the transceiver.

Note that you need at least two functional nodes for communication to be correct. If you add a silent node there must be at least two other nodes in the network.