Indexes - Indexes in grc to inscriptions in en

The links from indexed references to the single page of the corpus don’t work properly with grc indices. The reason seems to be that in the xml files a lot of elements (including titles) are not tagged with xml:lang=”grc” (simply because they are not in Ancient greek), hence they are not (well) displayed on the webpage; besides the not very elegant and time consuming solution of systematically duplicating those elements and adding a 'false' xml:lang='grc', is there the possiblity to change the behaviour of EFES’ indices?