You can achieve this through configuration. what you need to do is create a node "fieldConfig" (as nt:unstructured) and configure it with your custome xtype. you can also refer example /libs/foundation/components/video/designtab_profiles/items/profiles
Let me know if you need more information.
I hope above helps you.
Can You plz explain how to configure. bcoz i am very new to this topic.
thanks & regards,
Did you try to look at example /libs/foundation/components/video/designtab_profiles/items/profiles ? because it will give you idea about how you can configure it for your purpose. As you have mentioned, you want to configure custom xtype with multifield so am expecting you would be knowing which custom xtype you want to configure.