You can have more than one anchor defined. This comes in handy on images and dynamic window sizing to have two anchor points. The index is not param is not a attribute in the XML version but the index order of creation.
Code:
<Texture name="$(parent)TopDivider" textureFile="EsoUI/Art/Miscellaneous/horizontalDivider.dds">
<Dimensions y="4"/>
<Anchor point="TOPLEFT" offsetX="-80" offsetY="25" />
<Anchor point="TOPRIGHT" offsetX="80" offsetY="25" />
</Texture>
--halja