I have the following case:
All boats have a boat type like shark , yatch and so on. I need to register which type of boat name and also how many feet the boat is, but this is where the problem arises. If the user types in a shark I need to validate that its between 15-30 feet, if he type in a yatch it needs to be between 30-60 for instance. 

Any help on this?

```
<boat>
    <type>shark</type>
    <foot>18</foot> //validates
</boat>
<boat>
    <type>shark</type>
    <foot>14</foot> //fails
</boat>
<boat>
    <type>AnyOtherBoat</type>
    <foot>14</foot>//validates since its another type of boat than shark and yatch
</boat>

```

Help appriciated! Thx