[Gvozd]

.some-group .some-element {
    /* ... */
}

<div class="some-group">
    <div class="some-element">
    </div>
</div>

или

.some-group {
    /* ... base group styles ... */
}
.some-element1 {
    /* ... element1 overloaded styles ... */
}
.some-element2 {
    /* ... element2 overloaded styles ... */
}

<div class="some-group some-element1"></div>
<div class="some-group some-element2"></div>

Не?
Или вы как-то еще группируете элементы?