js backbone graph node - should I use a backbone collection?

graph.js

var GraphNode = Backbone.Model.extend({ 
    defaults: { parents: [], children: [], name: 'node' },
   
    addparent: function(parent) {
        if (!this.hasparent(parent)) {
            this.get('parents').push(parent)
            this.trigger('addparent',parent)
            parent.addchild(this)
            var self = this;
            parent.bind('destroy',function() { self.removeparent(parent) } )


            return parent
        }
        return undefined
    },

    addchild: function(child) {
        if (!this.haschild(child)) {
            var children = this.get('children')
            children.push(child)
            this.set({children: children})
            this.trigger('addchild',child)
            child.addparent(this)
            var self = this;
            child.bind('destroy',function() { self.removechild(child) } )

            return child
        }
        return undefined
    },

    bindchild: function(event,f) {
        this.bind('addchild',function(child) {
            child.bind(event,f)
        })

        this.bind('removechild',function(child) {
            child.unbind(event,f)
        })
    },

    unbindchild: function(event,f) {
        // not today :)
    },

    removeparent: function(searchparent) {
        var removed = false
        var self = this
        this.set({ parents : _.reject(this.get('parents'),function(parent) { if (parent == searchparent) { searchparent.removechild(self); removed = true; return true } })})
        if (removed) { this.trigger('removeparent',searchparent) }
    },

    removechild: function(searchchild) {
        var removed = false
        var self = this
        this.set({children: _.reject(this.get('children'),function(child) { if (child == searchchild) { searchchild.removechild(self); removed = true; return true } })})
        if (removed) { this.trigger('removechild',searchchild) }
    },

    hasparent: function(searchparent) {
        return _.find(this.get('parents'),function(parent) { return (parent === searchparent)  })
    },

    haschild: function(searchchild) {
        return _.find(this.get('children'),function(child) { return (child === searchchild)  })
    },

    parent: function() {
        var parents = this.get('parents')
        if (parents.length) { return parents[0] }
    },

    child: function() {
        var children = this.get('children')
        if (children.length) { return children[0] }
    },

    parents: function() {
        return this.get('parents')
    },

    children: function() {
        return this.get('children')
    },

    name: function() {
        return this.get('name')
    }
})