Take 2: Auto sync CRM Customer and project field details across 2 subsites on WP Multisite network

My WP Multisite network has two subsites that comprise similar CRM fields like (Organisation name, Milestone, Submitted Files). Subsite 1 uses the WPERP CRM plugin whilst Subsite 2 uses the UpStream Project Management plugin. However, despite these two subsites using the same (parent) database in WordPress, they currently do not sync the data in the right fields bidirectionally between themselves and update automatically to avoid the user having to edit them on each of the two sites separately. I need a solution for getting the each of the subsites to automatically inherit changes that are made in the other subsite. Thus, I want data that is entered in one subsite to show in the other subsite automatically, and in real-time. This may be a simple job of hooking the fields that are common to both plugins to the right table and field in the WP database. Thanks