adding a column with job title from othe rcolums

Hi,
I have the following question...

I have a list with employee numbers and employee descriptions as well as the supervisor for each employee
A: employee number
B: employee name
C: job title
D: supervisor

now I would like to add a column which gives me the job title of the supervisor

*which I will find, when I look him/her up as employee*
Is there any fast way of saying, that whenever this employee is a supervisor add the following job title?

I have tried a few but did not manage to automate the formula to work properly.
Thanks

thanks you very much