Sure, there is a function on the right hand side of the Group page called Merge Groups. This function allows you to include groups that you want to bring together, these could contain similar contacts, but you also have the option to exclude groups as well. This means any contacts that appear in a group that you decide to exclude, will not be brought across into the new group you are creating even if they are in the groups you are merging. 

This gives you greater control over who you communicate with and how you break your data up