From one license you can do this simply. Create two locations (Business Activity1 and Business Activity2) and two item categories (Business Activity1 Items and Business Activity2 Items, under this setup, you can create number of items related to the each business under these items categories) for your two businesses. From this setup, you can see the Profit Loss Statement by consolidate or location wise as well you can track the stock value by item category wise (means business wise).