How to make use of global variables to be able to access the table name

example:
I have 3 tables transaction for 3 branches
tbl_trans_001
tbl_trans_002
tbl_trans_003
branch code is already stored in the global variable ([var_branc])
How can I use these variables to access the table dynamically.

the grid
Select * from tbl_trans_ [var_branc]

and how well its implementation on the form

Maybe there are other ways to access the table according to their respective branches
thx