IDOC to JMS Sequencing issue

Hi Experts,

Interface details:

IDOC to JMS (MQ Series)

PI version- 7.0

Idocs are pushed to PI via background jobs for every 30 minutes, about 40 IDOCs are the average volume which hits PI.

IDOC's are sent in created sequence but from PI IDOCs are getting processed and in the same sequence the files are not getting created in MQ.

Eg:

IDOC Sequence: 1,2,3,4,5,6

When I check in MQ - Queue the sequence is like: 1,2,5,6,3,4

How do I ensure serialize delivery, this is impacting a lot .

Request your valuable inputs please

Thanks,

--Sai