Merge values from multiple 'Choose from list' properties

Scripting is probably the only way. You would need to create an array and then get lookup IDs from each of the properties and add them to the array. When done you can save that array to the combined property.

Ok, yea

Many thanks

Ok, yea

Many thanks

Here's what I ended up with

' H.EventHandler.MergeContactLists 
' Merge separate Contact lists into one combined list

' Filter by Object Type = Workflow
Dim iWorkflow : iWorkflow = Vault.ObjectTypeOperations.GetObjectTypeIDByAlias("H.Object.Workflow")
If ObjVer.Type = iWorkflow Then 
	
	' Filter by Class = Make Confidential
    Dim iClassId
    iClassId = Vault.ClassOperations.GetObjectClassIDByAlias("H.Class.MakeConfidential")
	Dim oPropVal : Set oPropVal = CreateObject("MFilesApi.PropertyValues")
	Set oPropVal = Vault.ObjectPropertyOperations.GetProperties(ObjVer)	
	If oPropVal.SearchForProperty(MFBuiltInPropertyDefClass).TypedValue.GetValueAsLookup.Item = iClassId Then 

'''''''''' Get the Users tagged on the Workflow in different properties
		' Property 1 - 'Named Project Users' - this is the first source that will be read from
		Dim oProp1Alias : oProp1Alias = "H.Property.NamedProjectUsers"
		Dim oLookup1 : Set oLookup1 = CreateObject("MFilesAPI.Lookup")
		Dim oLookups1 : Set oLookups1 = oPropVal.SearchForPropertyByAlias(Vault, oProp1Alias, True).TypedValue.GetValueAsLookups

        ' Property 2 - 'Named Project Approver' - this is an additional source that will be read from
		Dim oProp2Alias : oProp2Alias = "H.Property.NamedProjectApprover"
		Dim oLookup2 : Set oLookup2 = CreateObject("MFilesAPI.Lookup")
		Dim oLookups2 : Set oLookups2 = oPropVal.SearchForPropertyByAlias(Vault, oProp2Alias, True).TypedValue.GetValueAsLookups
		
		' Property 3 - 'Named Task Team Users' - this is an additional source that will be read from
		Dim oProp3Alias : oProp3Alias = "H.Property.NamedTaskTeamUsers"
		Dim oLookup3 : Set oLookup3 = CreateObject("MFilesAPI.Lookup")
		Dim oLookups3 : Set oLookups3 = oPropVal.SearchForPropertyByAlias(Vault, oProp3Alias, True).TypedValue.GetValueAsLookups

		' Property 4 - 'Named Project Task Team Approver' - this is an additional source that will be read from
		Dim oProp4Alias : oProp4Alias = "H.Property.NamedProjectTaskTeamApprover"
		Dim oLookup4 : Set oLookup4 = CreateObject("MFilesAPI.Lookup")
		Dim oLookups4 : Set oLookups4 = oPropVal.SearchForPropertyByAlias(Vault, oProp4Alias, True).TypedValue.GetValueAsLookups

		' Property 5 - 'Named Users' - this is an additional source that will be read from
		Dim oProp5Alias : oProp5Alias = "H.Property.NamedUsers"
		Dim oLookup5 : Set oLookup5 = CreateObject("MFilesAPI.Lookup")
		Dim oLookups5 : Set oLookups5 = oPropVal.SearchForPropertyByAlias(Vault, oProp5Alias, True).TypedValue.GetValueAsLookups
		
'''''''''' Combine the different properties into a single list
		' Create a temporary list starting with 'Named Project Users'
		Dim oDictionary : Set oDictionary = CreateObject("Scripting.Dictionary")
		For Each oLookup1 In oLookups1
		    Call oDictionary.Add(oLookup1.DisplayValue, 0)
		Next
		
		' If the 'Named Project Approver' does not already exist in the temporary list, add it to oLookups1 & update the temp list
		For Each oLookup2 In oLookups2
			If Not oDictionary.Exists(oLookup2.DisplayValue) Then 
				oLookups1.Add -1, oLookup2
				Call oDictionary.Add(oLookup2.DisplayValue, 0)
			End If
		Next

		' If the 'Named Task Team Users' does not already exist in the temporary list, add it to oLookups1 & update the temp list
		For Each oLookup3 In oLookups3
			If Not oDictionary.Exists(oLookup3.DisplayValue) Then 
				oLookups1.Add -1, oLookup3
				Call oDictionary.Add(oLookup3.DisplayValue, 0)
			End If
		Next

		' If the 'Named Project Task Team Approver' does not already exist in the temporary list, add it to oLookups1 
		For Each oLookup4 In oLookups4
			If Not oDictionary.Exists(oLookup4.DisplayValue) Then 
				oLookups1.Add -1, oLookup4
				Call oDictionary.Add(oLookup4.DisplayValue, 0)
			End If
		Next

		' If the 'Named Users' does not already exist in the temporary list, add it to oLookups1 
		For Each oLookup5 In oLookups5
			If Not oDictionary.Exists(oLookup5.DisplayValue) Then 
				oLookups1.Add -1, oLookup5
			End If
		Next

'''''''''' Write the combined list back to the object
		' Property CU - Existing list of Combined Users - this is the destination that will be written to
		Dim oPropCUAlias : oPropCUAlias = "H.Property.CombinedUsers"
		Dim oLookupCU : Set oLookupCU = CreateObject("MFilesAPI.Lookup")
		Dim oLookupsCU : Set oLookupsCU = oPropVal.SearchForPropertyByAlias(Vault, oPropCUAlias, True).TypedValue.GetValueAsLookups
		
		' Save the combined list back to the Workflow object
		Dim oPropertyValue : Set oPropertyValue = CreateObject("MFilesAPI.PropertyValue")
		oPropertyValue.TypedValue.SetValueToMultiSelectLookup(oLookups1)
		oPropertyValue.PropertyDef = Vault.PropertyDefOperations.GetPropertyDefIDByAlias(oPropCUAlias)
		
		Call Vault.ObjectPropertyOperations.SetProperty(ObjVer, oPropertyValue)

	End If ' End check for Class

End If ' End check for Object type