How to connect multi webCams

Hi everyone I would like to ask you how to connect more than two webcams via the USB port. I've connected three cams and built up the GUIDE interface for them. When I run the GUIDE, only two of them are activated and the third is said to be in use while it is not. I made sure of that and tested it over and over. By the way, I used axis to display the cam feed and all the necessay videoin and image functions. When I switch among the cams order, meaning the third one is turnd on first and so on, I only was able to operate two the third is always off or out of order. Is the Matlab limited to only two cams or there is a way to connect multi cams to the Matlab session? I thank you all in advance.