It is absolutely essential that you are not interrupted during guided reading and that your students know how important these lessons are to each group. If you are constantly being interrupted or having to manage the rest of your class while your students are reading you will not be able to do the very valuable monitoring that your students need.
There are a lot of programmes that help teachers with managing the rest of the class and a lot of them revolve around quiet, independent literacy activities that can be repeated day after day with changing content. They often involve rotating the students from activity to activity, usually coinciding with the end of each reading group lesson (every 10 minutes).
Don't be put off by those who say it is impossible for 5 year olds to work quietly and independently for 10 minute blocks of time. It can be challenging we know! BUT there is very sound research that highlights the incredible importance of students learning to stay on task and manage themselves, by themselves (in the presence of others) for periods of time. (The Dunedin Study). Think of it as not only a necessity for your sanity while taking reading groups, but also a vital life skill.
Quiet, independent work in a classroom of 5-7 year olds will not just happen. The activities need to be taught and you need to police quiet focussed work until they get the hang of it. At the beginning of the school year or a new term we recommend you take a week or two to set this up before even attempting reading groups.