Confession is a touchy subject for many. It can bring to mind scenarios and situations that are uncomfortable, or even humiliating. There are two classic sides to the tradition of confession (how we actually do it), both have serious issues. Whether you are talking with someone from a more "Orthodox" background (meaning Roman Catholic or Greek Orthodox and the like), then confession is often seen as a ritual between the individual and the priest. In the protestant traditions confession is often seen as public, usually during the invitation. Neither of these applications fully capture what it means to practice confession.
Though the Bible teaches confession, both in the Old and New Testaments, it doesn't give a lot of examples of exactly how it's done. Sometimes it's a private matter, just one on one. Sometimes its public, in front of the whole community. Sometimes the confession is from an individual, sometimes it's from the community as a whole. In short, looking at the Biblical examples confession can happen a lot of different ways and comprise a lot of different situations.
Here's what we need to remember in our small group discussions. The Bible doesn't give a formula and neither should we. Instead, how the person confesses and repents should be determined by the urging of their hearts, not some decision someone else made for them. For example. Most of my life I've heard the axiom, "Private sins can confess privately, public sins need to be confessed publicly." As often as those words get repeated, there is no Biblical command for such, which means it's personal opinion. That's not to say that there's not something to it. Frequently we will find our hearts and conscience push us in that direction. But sometimes it can be very hard to determine what is public and what is private. Something done privately can be made public by someone with a wagging tongue.
Another part of the problem when it comes to confession is that many seem to view it as a type of punishment. You did something wrong, now you need to be humiliated to pay for your sin. Nothing could be farther from the Biblical truth. Confession is ultimately between the individual and God, but like in so many aspects of our Spiritual lives, God wants us to interact with each other in the way that we would interact with him. That means, when someone confesses a sin or a struggle to me, God expects me to do as he would do and receive that person with love, comfort and acceptance. Only God can forgive sins, but he expects us to demonstrate that forgiveness to each other.
We are still early in our cycle and our groups are still fluctuating and haven't quite gelled yet, so don't expect a lot of confessions during your discussion. However, you need to be aware that as you go, if you are creating a safe environment, the practice of confession will start to happen more and more in our groups. It's at that time that the principles of confidentiality become so important to the group.