How to implement a limited set of 'tags' in doctrine?
===

Something about my data:
i'm currently developing a small webpage with php/symfony2/doctrine/postgres. Basically, i'm just gathering and displaying data from a couple of sites. The data is split into four groups: 'kids', 'teenagers', 'adults', 'seniors'. These tags won't change for a long time. I want to display a filter where you can decide which of the data you want to see. Since 80% of the users will be adults this should be the default. Also for teenagers it would be interesting to view data for teenagers and adults simultaneously (=> multi select).

**Question:**
What would be the best way to persist these 4 tags ('k', 't', 'a', 's') in my DataObject
each DataObject must have minimum one tag.

possible solutions i came up with:

1) Implement Tag as String (or pseudo enum) and store them in an ArrayCollection in the DataObject

=> seems like overkill

2) store the tags in an array (ColumnType=array)

=> hard to query with doctrine

3) store each tag as boolean column in the DataObject

=> doesn't feel right


I'm not really happy with any of these solutions. Any suggestions what i should do?