Create an Aris macro with context "Model opened" for one model type

I tested this in ARIS 10.0.7, if you use a different version you may have to find a different solution.

In the macro properties, when you tick that the macro is executed as the result of the event -> "Model opened" and close the dialogue window with the list of possible events with the OK button, you are led back to the Context page of the macro properties.

On this context page, while most of the stuff below the last radio button option remains greyed out (because you didn't select the last radio button, instead you selected the second radio button to make the report start with an event), you actually can tick model types.

Right click on any model type and deselect everything with the context menu option. Then scroll through the list of model types and only tick your CPE model type.