Thsi is now possible with our latest update of the editor.
You can now find the tab Assets in the top bar of the editor.
There you are able to create a new Collection and Category.
After you have created that, you can add the desired props to the category and edit the settings by clicking on the little gear icon between the name and the props image.
After having changed the settings you are able to copy the edited prop and change the cloned props settings.
Having created a few props with custom settings you like, you go back into the editor tab and open the Place Prop tool.
There you will find a dropout in the top area of the inspector, where you're able to choose My Collections.
Finally you click the yellow little die icon next to your collection and a random prop out of this collection will be placed.
I hope I explained it well enough