You need to create a decision service that decides whether to buy certain stocks or not. Here are the guiding rules:
Rule 1: Stock in debt is considered risky
Rule 2: Stocks in fusion with other stocks may be risky
Rule 3: Stock in fusion with a strong stock is not risky
Rule 4: Do not buy risky stocks unless they have a good price
Keep in mind that more rules that conflict with some of these rules can be added later. Link