How to set Target points to the User group?
You'll probably have to use the Rules module to make it happen.

Maybe create some kind of custom field (integer) to store the value of your target points value. ie. target points field = 100 points

Now, you can create a Rule to activate on the event "user awarded points", so that every time a user gets points, that rule is run.

Next, have that rule activate a different rule component, which is designed to compare the user's current points total with the value in the target points field. (So, every time somebody is awarded points, the system will check to see if they have met their target.)

You can set a condition such that, if the current point value is "less than" the  target value, run an action "display a message" with some text saying you need XX more points till you finish your target.

(You may need an additional step to run a calculation on the points needed, but I think you get the idea of what you need to do with my example.)