Certainly; it's really very simple. Much like grabbing any property from a TMXObjectGroup:

    m_tileMapNode = TMXTiledMap::create(filename);
    TMXObjectGroup *objectGroup = m_tileMapNode->getObjectGroup("Collision");
    CCARRAY_FOREACH( objectGroup->getObjects(), it) {
		Dictionary* dict = dynamic_cast<Dictionary*>(it);
		str = (String*)dict->objectForKey("rotation");
		long rot;
		rot = str->intValue();

		b2BodyDef bodyDef;
		bodyDef.angle = rot;