Or use IF-statements.
Load the sales_rep -field with different name in Financials and Goal table.
SUM(IF(goal_sales_rep = financials_sales_rep, Dollar_Amount, 0))
It won't be as fast as linking the tables together, but will work i hope.
better you can create star schema ,supose i ahve two tables and both tables are having same slecting dimensions ,
you can cancatenate both the table and connected to comman calendar,it will be better for you,other wise you can give association between two tables,if you have any dout let me know or please provide test data.