Processing records step-by-step

Hi experts

I have come across such requirement like the following:

1. Using filters to data source I retrieve some records

2. For each of retrieved records I need automatically take a field value (kind of ID) and retrieve records from the data source by the ID.

So, the problem is that for retrieved records only the first record is processed.

And my question is that how can I make processing along the whole table?

Thank you in advance.

Sincerely,

Anton