How to Append data to Workfront Planning Record with Fusion?

Hey all, I’m trying to build a Fusion automation to connect appropriate projects to records in Workfront Planning but the Planning Update Record module isn’t an append, it replaces any values currently in the field. What I’m trying to do is add a new project to the connected project field of a given record, while retaining the existing connected projects.

Whether this was clean or not, my idea of a workaround was to re-map all of the existing connected projects plus the new one, so I’m using the Planning Get a Record module to pull in the pertinent information on the specific record type I need to connect the project to. This is outputting a “Project” array that contains as many collections as there are currently connected projects, with each collection containing the External ID.

Then in a Planning Update Record module, I’m mapping the Project array external ID to the Project (Connection) field by using the array index number, plus the new project’s external ID as seen below.

 

This functions exactly as I need, the three existing connected projects plus the new project are all mapped to the connected project field. The issue is this method isn’t expandable. If there are four already connected projects when this runs, the fourth would not be included. I tried preemptively adding another mapping “data.Project[4].externalID”, but this causes the automation to error when there are not 4 collections within the array.

How can I go about appending this new project to the connected projects field, whether through an adjustment to what I’ve got so far, or an entirely different method, that is an append and not a replace, allows for any number of already connected projects, and doesn’t need any manual intervention to expand the array?

Thanks all!