Regarding transfer of spouse

I am a central govt employee and my wife is working as an assistant in icar.. I recently get posted to Delhi and accordingly my wife also requested in her institute to posted her any delhi based institute of icar... This is the 07th year of my wife in that institution and she completed all the terms and condition required for getting transfer .... Her institute is considering her request but with the condition of substitute, which is another way to say no to us as we do not find any substitute in the last seven year... Authorised strength of the assistant in the institute is 44 and out of that 41 assistant are presently posted there. If the case of my wife will be considered, than also the institute will be having more than 90 percent of it's authorised strength... The situation is so, if they can not considered such case now then they will never be able to consider any such case any time.... They are openly violating dopt guidelines by not following the order in true letter and spirit... What can we do in such case... Plz guide...