Hi Dale,
the answer is "Yes". This is what I am actually doing in of my my processes - so it is a proven working solution.
First, in a custom script, I calculate the assignees list, then put all of them into a single Process Assignees (gb_process_assignees) project attribute using the project write xog (all within the same custom gel script):
<Header version="6.0.11" action="write" objectType="project" externalSource="NIKU"/>
<Projects>
<Project name="${result.rows[0].name}" projectID="${result.rows[0].code}" billingType="I">
<CustomInformation>
<ColumnValue name="gb_process_assignees">
<core:forEach items="${group_members.rowsByIndex}" trim="true" var="row">
<Value>${row[0]}</Value>
</core:forEach>
</ColumnValue>
</CustomInformation>
</Project>
</Projects>
</NikuDataBus>
The gb_process_assignees attribute is defined as a Multi Valued Lookup - Number using a built-in Project Stakeholder (OBJ_PROJECT_STAKEHOLDER) lookup.
Then, I simply choose this attribute in the Assignees field of the Action Item (search for the Process Assignees field in the Resource Fields tab).
Sorry, if the description was too detailed, but other users (less experienced) might want to use it as well.
Happy using!
Pawel
#helpinghands