Thank you for reaching out and asking.
To help provide a possible solution we would like to better understand your setup. When you have a moment could you please provide the following information:
macOS version you are running on both your MacBook Pro (13-inch, Mid 2012) and MacBook Air (13-inch, Early 2015). You can find your macOS version by going to System Preferences… → About This Mac and within the window that opens up, you will see your macOS version listed.
The make and model of the projectors that you are wanting to connect to your MacBook.
Once we have this information, we will then be able to offer some possible suggestions that may satisfy your requirements.
Product Support Specialist