Sounds like you want to filter the results returned in the OData request. You can do this with the filter parameter in the URL.
For example, the URL would look like this:
GET http://localhost:8080/odata/published_odata_service/v1/POS_RetrieveAssetList?$filter=type eq 'MSA'
You can learn more about the filter parameter here: OData Query Options | Mendix Documentation