// customfield System Subtype

import com.onresolve.jira.groovy.user.FieldBehaviours
import groovy.transform.BaseScript
import static com.atlassian.jira.issue.IssueFieldConstants.*
import com.atlassian.jira.component.ComponentAccessor

@BaseScript FieldBehaviours fieldBehaviours

def systemSubtypeField = getFieldByName("System Subtype")
def customFieldManager = ComponentAccessor.getCustomFieldManager()
def optionsManager = ComponentAccessor.getOptionsManager()

def customField = customFieldManager.getCustomFieldObjectByName("System Subtype")
def config = customField.getRelevantConfig(getIssueContext())
def options = optionsManager.getOptions(config)

// Filter options
def allowedValues = ["Application Function", "Component", "Microservice", "Module", "NUDD", "Tool", "None"]
def filteredOptions = options.findAll {
    it.value in allowedValues
}

systemSubtypeField.setFieldOptions(filteredOptions)