Inserting multiple elements into another element in PrototypeJS?

In PrototypeJS, is there a more efficient way to insert multiple Element objects into an element? Here is the code I have now:

var calendar_elem = new Element('div', {'id': 'my_calendar'}).insert({    bottom: title_elem   // assume these are all Element objects}).insert({    bottom: days_of_week_elem}).insert({    bottom: month_calendar_elem}).insert({    bottom: footer_elem});

Can the bottom index contain an array, or must it contain only one Element/string of HTML? Would it be more efficient to get the HTML of each element being inserted, concatenate them, and pass that into bottom instead? Thanks!