redefine your object style for anchoring the group:
Turn off all options [-] but the one for the anchoring.
Thx that works
one more quention:
I have a group out of three elements. Is there a way to put a object Style with a contur just on the group. So that my 3 elements don´t have the contur style. Or do I have to creat a rectangle frame.
You have to use a rectangle frame.
The dotted rectangle that is showing the bounds of a group cannot be made with a stroke.
If you apply a stroke value to a selected group object, the elements in the group would get the stroke.