Emulating multithread in VBA/macro (creating multiple instances)

Hello All,
What I am trying to do is write a VBscript to create a VBA-threads (open/create 2 instances) of a Master.xlsm file to run 2 independent subroutines/functions at the same time [2 cores or threads] and then write the results back to the master.xlsm file. As these subroutines are very time intensive (takes 24 hours to complete in sequence).

What I have is a Workbook called Master.xlsm (MS Office 2013) which consists of:
Sheet1: contain data-entry for Table-A (used for subroutine 1) and Table-B (used for subroutine 2).
Sheet2: contain result-entry in Column-A (by subroutine 1) and Column-B (by subroutine 2).

Note: Master.xlsm also allow subroutines 1 & 2 to write to Sheet2 (Column A & B) while running.

Can anyone help me write a basic VBscript to be used as a reference or point me to the right direction?

Thank you,
ZeroKool