```json
{
    "yes": ["none", "guarantor", "co applicant"],
    "no": ["none", "guarantor", "co applicant"]
}
```

Based on the provided feature description, the possible values for the feature "other_parties" are "none", "guarantor", and "co applicant". 

Since the feature is categorical and has multiple categories, it is likely that the feature "other_parties" may have some relationship with the target variable. However, without having the specific data and performing the analysis, it is difficult to determine the exact relationship between the feature and the task.

As a result, it is suggested to include all the possible values of the "other_parties" feature for both the "yes" and "no" classes in the dictionary, as mentioned above. This provides a comprehensive representation of the feature for each target class.