Have an existing razor loop that retrieves  events  based on date. I need to fliter requests bases on event type in the query.   Using U7

Existing query:

var nodes = root.Descendants("CalendarItem").OrderBy("CalendarEventDayTimeStart").Where("CalendarEventDayTimeStart >= DateTime.Now.Date"  );

I need to filter using the value from a radio button:

I have used the following which works but not within the query above. Can this be combined to  limit records based on the event type  radio value? I don't want to include a nested if statement. I need to include within the initial query. 

if ( Umbraco.GetPreValueAsString(CurrentPage.eventtype) == "conference" )