Is this the same question? https://forum.mendix.com/link/questions/106922
If so; download the community common module from the appstore, and use the Java action “ StringSplit” to split your string variable into a list of objects, where , is your splitParameter.
You can only create a list of object, that is correct.
You may want to create a non persistable entity in your case, with an attribute. Then you will just have to create 3 objects of that entity, and put it in a list.
non persistable entity concept may fill out your requirement. You can understand Non persistable entity as a virtual stable which has no storage into database. non persistable entities can only present in app memory. as soon as we close the app the values are deleted. so this concept can help you out with your requirement.