Multiple-input dropdowns

So, I'm making a custom block that sends a message to a selected, and number of sprites at once, and only those sprites.
When in the input menu, I've noticed it's not possible to have a dropdown menu that also can be multiple-input.
I'd like to request that something like this be implemented, as it would be much easier than having to build a list block with the exact names of each sprite.

Edit: I was able to get it done with XML editing, but still would like it to be a feature.untitled script pic (5)

If you mean that you know in advance which sprites you want, you can make your own custom dropdown input. But that wouldn't solve the all-at-once part of your problem. You'll have to use FOR EACH ITEM, and if you want them all to happen at once, put it in a WARP block.

it is possible, by editing the xml. @wunder_wulfe's xml generation project is the easiest option for editing the xml to get what you want. Here's it's topic
Block XML Generator

Editing it how? I suppose you could change the dropdown's contents, but you can't change the semantics of the block to send to multiple destinations that way.