In reply to vlsique:
You want to start these sequences in parallel? You can use fork/join, this is easiest way:
fork
read_seq.start(read_agent.read_sequencer);
write_seq.start(write_agent.write_sequencer);
join
Fork/join will spawn 2 threads running parallel, each process will start a sequence with specific sequencer. It will wait for all threads finish before executing the next statement.