an array of strings as a jQuery selector?

Try the Array.join method:

var a = ["#p1", "#p2", "#p3", "#p4", "#p5"];
var s = a.join(", ");
//s should now be "#p1, #p2, #p3, ..."
$(s).whateverYouWant();

Well, there's 'join':

["#p1", "#p2", "#p3", "#p4", "#p5"].join(", ")

EDIT - Extra info:

It is possible to select an array of elements, problem is here you don't have the elements yet, just the selector strings. Any way you slice it you're gonna have to execute a search like .getElementById or use an actual jQuery select.

What about $(foo.join(", "))?