Disallowing gen_server:handle_cast() for a while?

[Nav]

Hi,

Is there a way to stop handle_cast(..) being called (i.e. stop
gen_server from reading data from queue) for a while?

I am trying to implement a logic, while processing, gen_server should
not accept any messages and let messages stay in its queue. (Other
processes can still send messages using gen_server:cast())

Does gen_server maintain separate message queue for each of its handle_cast?

While processing handle_cast(message1, ..), could it possibly process
handle_cast(message2,...) in parallel, if there is such message in
queue?
(What would in-built concurrency in gen_server mean exactly?)

cheers,

-Nav