Updating "Shapes" in PowerPoint

[MengS]

As a powerpoint designer currently in the design process, I want to be able to edit a logo that is used on many slides in many different positions on the slides so that a single edit to the logo will update all the logos on all the slides that utilize this logo (my logo is a "group" in powerpoint comprised of an image of a dog and some text).
I found that utilizing master slides was cumbersome as my logo is on many different positions in my slides (sometimes the logo is in the center of a slide, on another slide - the logo is on the left).
Adding a "storyboard shape" was great - but I can't update the shape...