Populate Multi Select Combo Box with People Display Names From SharePoint List

[molen]

Hi -

I have received some great info on this site before!  Hopefully someone has a idea here.

I have a SharePoint list that has People data in it in a couple of different columns.  I am using a Gallery to allow user to pick a SharePoint row that they want to work with.

I can populate a single select combo box with data from my SharePoint list.

The DefaultSelectedItems property is set to the following:

[LookUp('A1A Request Intake',ID=Gallery1.Selected.ID,'Functional Business Sponsor'.DisplayName)]

That code allows me to populate the combo boxes with the people picker name that is listed on the SharePoint site.

That code will not work for a ComboBox that is multiselect.  I am almost positive that I need to use a filter but I can not figure it out.  I feel like the code should be something like this for the DefaultSelectedItems property:

[Filter('GCS Request Intake',ID=Gallery1.Selected.ID,'Request Owner(s)'.DisplayName)]

That does not work.  Any ideas?