Hi Jamal, what kind of group are you talking about? Is it children, teenagers, adults? How long are you here for and what is the purpose of your trip?
Unfortunately I'll start with the warnings - there is a lot of petty crime in certain parts of the city. For example when walking the smaller streets of Ciudad Vieja (the old city - worth seeing for beautiful buildings) you have to be street smart. Don't show off cameras or carry many things. Be warned that you will regularly be approached and somewhat hassled in this part of town.
This is also where a lot of the social nightlife spots are located so exercise care and be sure your group know how to get back to wherever you are staying.
On the other hand Montevideo is a great little city full of wonderful activities if you're willing to look for them. Check out some of the wonderful art galleries and cultural events and definitely seek out some candombe on the streets in Barrio Sur or Palermo on Saturday and Sunday nights.
This is a good place to find some cultural and art events, but the page is all in Spanish.
