A single java project can contain as many test suites as required. The real question developer might need to answer is what type of modularization is preferred or fit for the project. I would recommend to start with one project only.
Developers have to share this Java project with tests inside, though VCS, among themselves.
For headless execution of tests, there is a built-in Test Suite Executor project which contains required Ant scripts and targets which can be invoked against any local/remote Integration Servers. Configuring the same and executing through CI/CD tools such as Jenkins is fairly simple.
Let me share couple of topics which has very detailed info on this. Let me know what you think.