Accessing the samples of a participant

It currently isn't possible to access a participant's sample attributes directly, using this.samples.<attribute>
This is a significant limitation for analyses across samples (e.g., tissues, cell types) from the same individual.
As a workaround, I'm adding sample lists through the API:

{"samples_": {
    "itemsType": "EntityReference",
    "items": [{"entityType": "sample", "entityName": i} for i in participant_sample_ids]
}}

Since this can lead to synchronization problems, it would be great if the participant->samples relationship were implicit in the data model.