Hiring friends into your startup is a mixed blessing. The good part is that you know your friend's strengths and weaknesses and whether they share your values. If, on top of that, your friend brings a skill your startup needs, bringing a friend into your startup can be great.

Still, you might have to choose between supporting your friend and being a good boss. Sometimes being a good boss means delivering difficult feedback to an employee. And if that employee is your friend, the friendship might not survive the harsh feedback.

Such conversations are the least favorite thing about entrepreneurship for Kim Jordan, founder and CEO of New Belgium Brewing. She dislikes the loneliness at the top -- which becomes even lonelier when it comes time to give harsh feedback to people whom she "grew up with," according to The Wall Street Journal.

In her view, the most difficult part of being the boss is drawing the line between acceptable and unacceptable behavior. Jordan explained, "That feels particularly negative when it's people who are your friends," which leads to "emotional murkiness." 

If you hire friends or you feel as though your employees have become your friends, here are four things you can do to lower the chances that acting as a boss will destroy those friendships.

1. Overcommunicate Your Company's Culture.

If everyone in your company is getting a consistent message about what kind of behavior you prize most highly, all employees should know where the line is drawn.

Devote 20 percent of your time to articulating and communicating your company's values and telling stories about employees who act accordingly. When you hold all-company meetings, if your company cherishes going the extra mile for the customer, make sure each meeting starts by celebrating employees who lived that value.

If you clearly and consistently communicate your culture, then should you get a call from a customer complaining about how your friend in the company promised the customer something they did not deliver, you will have an easier time starting the unpleasant conversation with your friend.

2. If a Friend Crosses the Line, Tell Them Right Away.

It's perfectly natural for you to want to avoid letting your friend know you've heard the bad news from the customer. One of the reasons you get the big bucks is that you have to do the opposite -- and confront that misbehaving friend right away.

If you wait, other employees will find out and you will discourage everyone in your company who is trying to do the right thing.

3. Frame the Conversation in a Balanced Way.

How can you deliver the harsh feedback and preserve your friendship? Start off by continuing a conversation you last had about a common interest or a family member. Next bring up the employee who went the extra mile for your customer that you discussed at the last staff meeting that your friend attended.

Deliver the bad news: You spoke with the customer who was disappointed that your friend had failed to deliver on a promise. Then let your friend talk. Your response will depend on how the friend responds. If your friend offers a sincere apology followed by a specific action plan to win back the customer's trust, there is hope that the friend can be rehabilitated professionally.

4. If You Must Fire a Friend, Do It Humanely.

If the friend makes excuses and fails to take responsibility for the problem and the solution, you may need to have an even more difficult conversation. If this is the second or third such conversation, you will have to tell your friend to leave the company. Give your friend a fair severance package and offer outplacement counseling if you can afford it.

If you fail to engage a friend in such difficult conversations, you may be putting your company's entire future at risk. The good news is that if you follow these four steps, you may be able to preserve the friendship while protecting your company for all the employees who are doing the right thing.