How to instruct Oracle 11g Standby database MRP to bring down as soon as applying the given archive log file? Scenario:
Let us consider the following:
Oracle 3 node RAC.
RMAN Managed Recovery and Dataguard are configured between production and standby DBs.
The SCNs of 3 nodes are S1, S2, S3 at some point of time respectively. 
Smax=max(S1,S2,S3)
Update1(with reference to Balazs Papp Advice):
log_1_x.arc, log_2_y.arc, log_3_z.arc where log file sequence number x&lt;y&lt;z and they contain the sequence number Smax

Please advise on bringing down Orace 11g Standby database MRP as soon as applying the given archive log file with name, log_3_z.arc!
archive_xyz.log contains the sequence number Smax


This is where you are wrong. You have 3 instances, you have 3 redo threads, so you have 3 archivelogs containing the change at Smax. 

Because of this, you need to recover the database until SCN/change, not "archive_xyz.log".



alter database recover managed standby database until change Smax;


Note that, this does not apply the change at Smax.

managed_standby_recovery::=


  UNTIL CHANGE Clause
  
  Use this clause to instruct Redo Apply to recover redo data up to, but
  not including, the specified system change number.