Hi,
Did you provide any validation to your system to prompt error message by showing purchasing group and plant belong to different company code/purchasing organization.
Releasing PR for different purchasing organization/company code - you should create different roles for each case. For example
R1--Company code 3000 and purchase organization 212
R2--Company code 2000 and other purchase organizations
Discuss with Basis consultant and go for authorization concept, and allow to release PR with a release code by allowing(SU01) a Role for user for particular company code and purchase organization.
NOTE: User training should be provided, so that PR should be created on basis allowed components. for respective user.
Regards,
Biju K