Just add the following three lines into the SoapUI Groovy Script.
def project= testRunner.testCase.testSuite.project.workspace.getProjectByName("projectName")
def runner = project.testSuites['testSuiteName'].testCases['testCaseName'].testSteps["groovyScriptName"].run(testRunner, context)
log.info ("runner status ....... : " + runner.getStatus()) // prints the response of the nested script in the log
Change the projectName, testSuiteName, testCaseName, groovyScriptName according to your SoapUI Project. (groovyScriptName is the script which needs to be called)
It just worked on me, and ran a Groovy Script from another groovy script.
Ps: Just in case to verify if the project is being called properly,
add the following code line in between the def project and def runner.
log.info project.name // just to verify the project
test.groovydoes? - Rao