As far as I know, this requirement cannot be handled directly from the Mendix side. The Expand One Level call simply asks Teamcenter to expand the BOM, and Mendix does not have an option to exclude specific object types at request time.
If the goal is to make sure certain object types never come back from Teamcenter at all, this needs to be handled on the Teamcenter side. A common and recommended solution is to work with the Teamcenter admin / PLM team and have them adjust the relevant revision rules, structure filters, or BOM window configuration so those object types are excluded during the expand operation.
So the best next step would be to discuss this requirement with the Teamcenter/PLM team and agree on the appropriate rule-based solution there.