I am trying to model the time until some event occurs for individuals observed over a 24 month period. 

For about 75% of people, no event occurs. For 15% of people, we know exact time of the event. For the other 10%, we only know a time window in which it occurs. So some sample "survival times" might be: 

    >24 
    2.5 
    >24 
    5.0 
    0 to 6
    6 to 12 
    >24 
    18 to 24 

and so on. Can this type of data be accommodated within "standard" survival models? If so, some hint at how to construct the `Surv()` object in `R` and how to pass it to `survreg` would be appreciated.