Unplanned sequential interviews with different groups
In general you do not have to disclose the exact order or reason for data collection. Most papers are ‘narratives’ written with the available totality of data at this point. Constructs such as ‘because we found xyz we then tested if abc...’ don’t necessarily describe the actual order of events.
The only times where this is truly relevant is when you run statistical tests. For example, if you collected data from the first group and analysis made you collect a larger dataset that now jointly gets analyzed, this has to be stated and included in the statistical analysis.