String manipulation in Java 8 Streams

I have a stream of Strings like- Token1:Token2:Token3 Here ':' is delimiter character. Here Token3 String may contain delimiter character in it or may be absent. We have to convert this stream into map with Token1 as key and value is array of two strings- array[0] = Token2 and array[1] = Token3 if Token3 is present, else null. I have tried something like-

return Arrays.stream(inputArray)
            .map( elem -> elem.split(":"))
            .filter( elem -> elem.length==2 )
            .collect(Collectors.toMap( e-> e[0], e -> {e[1],e[2]}));

But It didn't work. Beside that it do not handle the case if Token3 is absent or contain delimiter character in it.

How can I accomplish it in Java8 lambda expressions?