Repeat where value is null

Hi folks,
I have a repeat row from a Server Connect API connection that I only want to return the top 7 records.
This works as expected.

<tr dmx-repeat:users="serverconnectUsers.data.apiUsers.data.$resources.top(7)">

I am struggling within the repeat to exclude records that have one of the values set.
here is a sample of data

{
   "apiUsers":{
      "status":200,
      "headers":{
         "cache-control":"private",
         "pragma":"no-cache",
         "content-type":"application/json;charset=UTF-8",
         "expires":"0",
      },
      "data":{
         "$resources":[
            {
               "$key":3505,
               "$url":"my server url",
               "user_UserID":27,
               "user_logout":"2020-09-01T10:31:47+01:00",
            },
			            {
               "$key":3506,
               "$url":"my server url",
               "user_UserID":28,
               "user_logout":null,
            }
         ]
      }
   }
}

I only want to list the values where user_logout is null (userid 28)
Thanks in advance