Hi Kostas,
No there isnt.
Its unfortunate Twitter is behind the times and not offering admin/user accounts yet to allow this type of functionality especially when Facebook have already launched the 4 levels of control for Facebook pages.
People have asked Twitter before when they are going to make this available as its such an easy thing for them to implement…however unfortunately they’ve decided its not a feature they want to add natively and yes you need to use a third party app to achieve this functionality at the moment.
Cheers
Dean Collins
http://www.Cognation.net