field where you can select dates and store as multivalued field

I have a table of unique ids which stores patient names and last names, in another table that's linked to the first table that has start date of service and end date of service for each unique id. what would be the best option for me so that inside the second table each field can have multiple dates for specific service done within the Date of service(DoS) start date and DoS End date.

Example
Level 1
Id Name
1 John doe
Level 2
Dos Start 11/25/2013
Dos End 11/30/2013

Level 3
Service A done
11/25/2013
11/26/2013
11/28/2013
11/30/2013

bold text are separate fields

Thanks