Thanks for the details.
Do you know how to select the centerpoint ("center of gravity") of the cylindrical face directly on creation of that face to point connector ?
In the Dialog where you generate the RBE Spider Element, you can directly select the origin of a curve or circle to position the node for the spider element. You will find a tutorial in the NX 11 documentation, that is showing how to generate the RBE elements:
However, in this tutorial you will connect the circular edge with the centerpoint. If you want to connect the cylindric face to the center point of the Cylinderface, you should do it as follows:
When you select the "1D Connection --> Point to Face" functionality, when defining the "Source" point, please select "Between two points" and select the top and bottom edge of your cylindric face.