Can CSS traverse up the tree to the parent of a clicked element and get the parent sibling?

Question

I have the following code:

<div class="someClass">
    <input class="myInput"/>
</div>
<div>
    <ul class="myList">
        <li></li>
    </ul>
</div>

What I'd like to do is change a property on the <ul> when input:focus

Possible or not possible? Thanks for any responses.