vlookup formula and function to combined with another formula

Hi all..

i have two excel files which are data and master..both files will be use for salary calculating.. the vlookup formula will be use in master files for dragging the salary data from Data files..the formula as follow
VLOOKUP(B4:B225,'D:\Salary\[Data.xls]AUG'!A$1:F$65536,6,FALSE))

the vlookup working fine to me.. but my problems is i want the data to be auto calculated when they have same value in two columns.. or if the name is similar/match in two columns (one for salary and another one for overtime), the salary should be auto calculated.

Data files will contain of these:
a:Employee ID
b:employee name
c:Employee salary/Overtime

Master files will contain of these:
a:Employee ID
b:Emplyee Name
c:Employee Nett Salary (that will be dragging from Data files)

is there any formula that i can used to combined with my vlookup formula?

appreciate any help! thanks!!