Possible to disable parallel execution for a selection modules/tests?

I do have a multi-module project building via Java 8 and Gradle 3.2. I typically build the project at the root via the --parallel flag, but I have noticed that there are certain modules whose tests need to be run in non-parallel mode. These are typically tests that tend to create a type of a [web|database|etc] connection on a port and bind to it on every run. As an intermediate option, without doing surgery on the codebase just yet, I want to ask:

Is it possible to disable parallel execution for a selection modules only? and perhaps limit parallel execution to src vs. test?

Having scanned the docs, I didnt find an option. I realize the better option is to perhaps isolate and reorganize how tests run but am curious if there is an “easier” solution I can adopt temporarily while refactoring takes place.

Thank you.