Adding Constraint to Join Table

[cujo]

I have a domain class that looks something like this...

class Foo{
String name
static hasMany=[goos:String]
}

The problem I keep running into is that I need each "goo" to be larger than the default 256.  Does grails allow me to set that value?  I know how to set it for the "name" attribute, but not for something in a join table.