You have to create part family to use them in an assembly like there are a couple of family members are used in the assembly that you have shown.
Start with this link 'Create a simple part family'. You will find other related topics in the NX documentation.
Import to Teamcenter: Gives error on these "family parts" ?
Are these "family parts" Teamcenter friendly and combatible with it ?
Is the solution to replace these "family parts" with similar ordinary parts.
Or can I delete "family"-connection easily ?