It is hard to understand what you ask without source code example.
By default you can expect such behavior with BAS scripts. In each iteration
Bas would use one value per thread.
When creating resource you should use option "Lines from file and "Use each line one time". And your resource TXT file should have a structure like this >
A1
A2
A3
A4
If that is the case each thread iteration will use only one value, even in multithreaded enviroment.