HTML_CSS : The Definitive Guide

Remember, when several selectors share the same declarations, they may be grouped together to save writing the same rule more than once. Each selector must be separated by a comma.

Two cases exists to handle group of selector. The quick and limited solution (accept only two selectors in a same group) with : HTML_CSS::setSameStyle(). And the extended/common solution with : HTML_CSS::createGroup(), HTML_CSS::setGroupStyle(), HTML_CSS::addGroupSelector() and HTML_CSS::removeGroupSelector().