Merging/Linking Multiple PHP scripts to work together

We want to merge / link 3 PHP Scripts so that they can all communicate with each other, use the same user base but also have some kind of independence from each other as well. This is a social network that will act as a instagram / netflix / amazon style website 1. The Social network side would work with this script [login to view URL] [login to view URL] Netflix/Youtube side would work with this script [login to view URL] [login to view URL] Amazon/Ecommerce side would work with Wordpress/woocommerce Basically Wowonder would be the social feed that videos from PlayTube can be shared to or posted on and same with products from woo commerce. Now the tricky part is these will need to be able to communicate with each other. Examples below 1. If a playtube video is shared to the Wowonder then we need to sync likes, comments to both playtube and wowonder. 2. If a video is posted to on WoWonder it would use PlayTube to upload and manage that video. 3. Products from the Wordpress section would be able to be shared to the wowonder feed Etc if you have questions about the above let me know.