SQL Server 2012+ Agent Job with Parameter to determine job flow
Expanding a bit on what @Nic said in his comment.  Create a quick table in an applicable database.

CREATE TABLE JobParam AS (Param1 varchar(50))


Then set it appropriately before you start your job.

UPDATE JobParam SET Param1 = 'JobPath1'


As Nic suggested I would put some code at the top of steps 6+ like such.

IF (SELECT 1 FROM JobParam WHERE Param1 = 'JobPath1')
BEGIN
    T-SQL statements
END


Another option is to put code in the job that causes a failure if the param has a specific value and use the fail/succeed logic of the job steps to branch your job.

Either way I would make sure to put in a step at the end that always runs and re-sets your value to a default in case the job is run but someone forgot to update the parameter.  Maybe have the default bypass the entire job.

UPDATE JobParam SET Param1 = 'FailJob'