One thing you can do is add the same label (or group name) to each contact that you want to add to that group. Then, when creating messages type the group name/label that you made and you will see all of the contacts that have that label. Add each of them to the message you want to send. It's not as simple as just being able to type the group name and the message automatically goes to everyone in it, but it's one way to acheive the same end result. There might be an easier way to do this, but I haven't really tried to do so. I've used the method I mentioned when trying to make sure I send the message to everyone in my organization and it works for me..but if you are sending it to a large group then it might be tedious.
Thank you for assisting kobimom. The information provided is very helpful. There is also an application that can be downloaded from the App Store that will allow you to set up Groups. Go to your App Store and search for Group!, download the application. This seems to be a free application and once you download it your contacts will automatically sync. Follow instructions on how to add groups.
H! Thanks for the helpful replies. I have downloaded the Group! app and it seemed to be exactly what I was looking for. However, once Iset up and save the groups and leave the app, they are all gone the next time I go into the app. The groups are still there but the contacts in each group are gone. I have tried many times and the exact same thing happens. Has this happened to anyone else? I saw that there is another app called Group, and I was wondering if it is the same app. Again, any help would be much appreciated.