English to Polish Law/Patents Law (general) Testament

Już zadałam dzisiaj pytanie dotyczące tego zdania, ale przy sprawdzaniu tłumaczenia nabrałam wątpliwości, co znaczy "of their own number".

W punkcie testamentu dotyczącym uprawnień jego wykonawców:

My Executors shall have the fullest power, of retention, realisation, investment, appropriation, transfer of property without realisation and management of my estate as if they were absolute beneficial owners; and shall have power to resign office and to appoint one or more of their own number to act as solicitor or agent in any other capacity and to allow him or them the same remuneration to which he or they would have been entitled if not an Executor or Executors.

Czy chodzi o wybieranie spośród siebie?