Sencha Extjs 4 Geekies around ?

I have a scenario that i want my grid filters to have a different xtype than the one being used by the column field ....

ie..

my json

{
    "header": "First Name 25224",
    "dataIndex": "first_name_25224_6",
    "sortable": true,
    "flex": 1,
    "hidden": false,
    "filter": {
      "xtype": "list",
      "options": [
        "Abass",
        "Abdi",
        "Abdikafi",
        "Abdikarim",
        "Abdilahi",
        "Abdinassir",
        "Abdiqadir",
        "Abdirahman"
        ],
     "labelField": "value",
     "phpMode": true
   },
    "editor": {
      "xtype": "textfield",
      "allowBlank": true,
    }
}

As from json above my Filter is a list but my Field(editor) is a sting (textfield) ...... Any info i would hack that .....