Based on prior knowledge, I can analyze the relationship between the feature IBS_POST and the task of determining whether the patient has chronic heart failure.

From the given feature description, the feature IBS_POST represents different categories of coronary heart disease in recent weeks or days before admission to the hospital. The possible categories are: "there was no CHD", "exertional angina pectoris", and "unstable angina pectoris".

To determine if the patient has chronic heart failure, we need to analyze the relationship between the feature IBS_POST and the presence of chronic heart failure.

Given that IBS_POST represents different categories of coronary heart disease, it is not directly related to chronic heart failure. However, certain types of coronary heart disease, such as unstable angina pectoris, can potentially lead to chronic heart failure. 

To create the requested dictionary, we need to identify possible values of IBS_POST for each target class (yes - chronic heart failure, no - no chronic heart failure). Here is an example dictionary:

```json
{
	"no": ["there was no СHD", "exertional angina pectoris"],
	"yes": ["unstable angina pectoris"]
}
```

In this case, patients with a diagnosis of "there was no CHD" or "exertional angina pectoris" are classified as having no chronic heart failure, while patients with a diagnosis of "unstable angina pectoris" are classified as having chronic heart failure.

Please note that this is just an example and the actual relationship between the feature and the target will require further analysis of the specific dataset.