Concatenate Integration object IO Field with multiple IO instances

Hello - What is the best way to Concatenate Integration object IO Field with multiple IO instances. Here is the IO instance

and I would like to get  AreaOfPractice value as A;B;C

I know we can do it via script. Is there any non-script/declarative option do do this?

<ListOfAccount>

   <Account>

        <AreaOfPractice>A<\AreaOfPractice>

    </Account> 

  <Account>

        <AreaOfPractice>B<\AreaOfPractice>

    </Account>

  <Account>

        <AreaOfPractice>C<\AreaOfPractice>

    </Account>

</ListOfAccount>

Thanks