It is advisable to bifurcate the interest amoong 28 deductees and make the payment of Interest on delayed deposit of TDS and file the Return if you have not filed or file revise Return if TDS Return not yet filed.
Bifurcation is required since the Notice that you will be receiving from the TDS Department will calculate Interest on each and every deductee for late payment of TDS.
it would be better if you can file the revised return for the interest in the delay payment of TDS..................after filing of revised return ..just write a letter to the concern ITO -TDS and enclose the copy of challan for interest.
Need not to provide deductee wise bifurcation on Interest paid... You just have to pay interest and put amount in interest column in challan with respect to section. Please take care of interest payment section wise. After interest payment you also have to revised TDS return with interest payment challan details. After revising TDS return you may check online though TAN login whether default is still exist or not.