A blurry line exists for some, between soul groups and spirit guides. Please see my previous article on Soul Groups and another on Spirit Guides. Half your soul group may incarnate within a human generation and the other half may stay behind spirit-side and watch over those incarnate. These members of the soul group would therefore be classed as guiding entities because they are helping, guiding and guarding their companions. This section of your soul group may help to intuitively keep you on track within your life plan, and impart helpful knowledge or set up some synchronicities now and then.
Therefore, it's understandable that there's a bit of a blurry line between the soul group and the spirit guides. Spirit guides however have a clear purpose, to help and guide you during your earthly experience. They are more often, advanced souls that we call upon to impart wisdom especially in a time of need, either subconsciously, or consciously if you are 'spiritually awakened'. Advanced souls come to the aid of less advance souls. Similar to this reality; adults assist and guide children and young people. So in these cases, the spirit guides are not part of the soul group, but often entities allocated to us from within the alternate layers of existence associated with Earth. Instead of being our contemporaries, they are more like our teachers, our aids and occasionally our angels.