Succession and administration

My 11 brother and sisters , including 2nd mother file succesion for pension and bank balance of our father .

This appliaction is about to order, but one of my sister who didnot have joined us in court, that is legal heir no 12 is saying to add letter of administration prayer also in this application, other wise she will not join us in court.
The judge sahib also order us to bring her affidavit before order given.
Can another application for immovable property in the same sma destroy/ delay our present application for many years.........?