Based on prior knowledge, the blood glucose levels can be used as an indicator to predict age groups. Senior individuals generally have higher blood glucose levels compared to non-seniors. 

For the feature LBXGLU, we can define the following ranges of values to determine the age group:

- Adult: Blood glucose levels below 100 mg/dL.
- Senior: Blood glucose levels equal to or above 100 mg/dL.

Based on this analysis, we can create the dictionary as follows:

```json
{
	"Adult": [80.5, 92.0, 85.3, 91.7, 95.2],
	"Senior": [103.2, 110.1, 98.9, 102.5, 108.0]
}
```

Please note that these values are just examples and it is recommended to use a larger dataset with actual values to obtain more accurate ranges.