Access other datasource from a BasicDataSource

Hi,

I have a solution where I have two separate datasources that access the same database table.

One datasource ds1, is used to search and retrieve data from this table, and is joined with a number of other tables with aggregated fields.

The other datasource, ds2, is a BasicDatasource extension that is used for saving records.

In executeAdd and executeUpdate in ds2, I need to detect what primary key d1 is using.

So, I´m looking for a way to find the DataSource instance for ds1 in ds2? How can I access other datasources from a custom datasource?

Regards
Rolf