How to create oracle user for more than one version

I have server under RHEL 6.3 installed on that server Oracle 11gr2 and 12c, I want to create user lets say Ahmad but I want this user to be sysdba on both servers, for single server I edit .bach_profile to be like the following: 11g: ORACLE_HOSTNAME=oracledev; export ORACLE_HOSTNAME ORACLE_UNQNAME=DB11G; export ORACLE_UNQNAME ORACLE_BASE=/oracle11gr2/u01/app/oracle; export ORACLE_BASE ORACLE_HOME=$ORACLE_BASE/product/11.2.0/db_1; export ORACLE_HOME ORACLE_SID=DB11G; export ORACLE_SID PATH=/usr/sbin:$PATH; export PATH PATH=$ORACLE_HOME/bin:$PATH; export PATH LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib; export LD_LIBRARY_PATH CLASSPATH=$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib; export CLASSPATH PATH=$PATH:$HOME/bin unset USERNAME cd $ORACLE_BASE export PATH and if I want to make him sysdba for 12c I use the following: export TMP=/tmp export TMPDIR=$TMP export ORACLE_HOSTNAME=oracledev export ORACLE_UNQNAME=cdb1 export ORACLE_BASE=/oracle12c/u01/app/oracle export ORACLE_HOME=$ORACLE_BASE/product/12.1.0/db_1 export ORACLE_SID=cdb1 export PATH=/usr/sbin:$PATH export PATH=$ORACLE_HOME/bin:$PATH export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib export CLASSPATH=$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib My question is it possible to marge those parameters together without making a conflict, if yes please advise