Hello Don,
I realize this comment is too late to be of use to you and I apologize for that. As part of an effort to clean up Matlab Answers, I will be posting the answer for others who may use it as a reference.
The Simulink tool itself does not have the ability to automatically identify which points are stable. You would have to write a post processing script in matlab to look at the dynamic results and identify which points are stable. You can then pull these points specifically from the saved data set and create the bifurcation diagram that way.
Matlab also doesn't have built in support for bifucation diagrams. These post addresses it somewhat: https://www.mathworks.com/matlabcentral/answers/99328-how-do-i-create-a-bifurcation-diagram-in-matlab
Regards,
Joel
