Export/Import/SQL Loader :: Skip Import Of A Schema In Dumpfile?

version:11.2.0.3
Platform : RHEL 5.4

Imagine you have 100 schemas backed up (expdp) in a dumpfile and you want to import just one schema from that dumpfile in a DB. You can specify just that one schema you want using SCHEMAS parameter in the impdp. But things are not straightforward when you want use REMAP_SCHEMA.

Here is my scenario:
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I took the expdp dump of schemas A and B in one go. So, dumpfile has objects from both A and B.The dumpfile name is : schemas_AandB.dmpNow , I want to create schema C from A using REMAP_SCHEMA parameter

-- Putting each parameter in a separate line for readability
impdp PSTREF/PSTREF_123
DIRECTORY=ADET_EFX_DIR
DUMPFILE=schemas_AandB.dmp
LOGFILE=CreatingCfromA-Impdp.log
REMAP_SCHEMA=A:CEverything goes fine. Schema C is created from Schema A in the dumpfile.

But impdp is trying to create schema B as well because schema B was present in the dumpfile. Since the schema B and its objects are already in the DB , I get the following errors.

ORA-31684: Object type USER:"B" already exists
ORA-31684: Object type PROCEDURE:"B"."SP_CLEAREXPIREDSESSIONDATA" already exists
ORA-31684: Object type PROCEDURE:"B"."SP_DELETESESSIONDATA" already exists
ORA-31684: Object type PROCEDURE:"B"."SP_DELETESTATECONTEXTINFO" already exists

[code]...

Trying to avoid schema B in the dumpfile from being imported by specifying SCHEMASBut I got the following error
ORA-39065: unexpected master process exception in MAIN
ORA-12801: error signaled in parallel query server PZ99, instance oracth214:HEWRAC1 (1)
ORA-01460: unimplemented or unreasonable conversion requestedMaybe REMAP_SCHEMA and SCHEMAS parameters won't work together.

Is there any way to prevent the impdp from importing user B and its objects ?