SQL & PL/SQL

Hello All,
We are migrating our MySQL Database to Oracle and we are facing the GROUP_CONCAT in built function of MySQL.
I have gone through the WM CONCAT, COLLECT AND other functions built from the Oracle aggregate packages . Our problem is this:
table A(emp_number, emp_firstname, emp_lastname, emp_status) and table B(emp_reporting_mode, emp_sub_mode, emp_sup_mode); Here emp_sup_mode represents the the employee
Those tables are not related and we have such data
Table A
emp_number emp_firstname emp_lastname emp_status
5 Raoul ESSOME STA000
6 Nadine YAYA NULL
1 Hermann LONDJI STA001
14 Honore ONANA STAT00

Table B
emp_reporting_mode emp_sup_mode emp_sub_mode
1 6 1
1 14 5
The emp_sup_mode represents the supervisor emp_number and emp_sub_mode represents the subordinate emp_number. MySQl was able to use the GROUP_CONCAT to concatenate this.
is as such and should output the emp_firstname and the emp_lastname of the supervisor where the supervisor code is the equivalence of the employee number. Here, we can see Nadine YAYA (emp_number 6) is the supervisor to Hermann LONDJI (emp_number 1) and Honore ONANA (emp_number 14) is the supervisor to Raoul ESSOME (emp_number 5).
Thanks for any input. Other methods and fuctions rather aggregate from similar id and cos.