I have a query regarding the best approach to a problem. I have a table that holds related information and changes daily . An example is below:

The table has 12000 record.
Each record is related to a group_id. e.g. Out of this 12000, 5 records will be related by group_id ABC, another 8 by group_id DBG etc. Each record within a group has 2 its own currency and amount which must be stored (NB the amount of rows in a group will change), as these amounts must be converted and updated to another amount using the currency of the master record in each group which identifiable with the Master ID. The rates for conversion e.g. GBP to USD, will need to be linked via a join? to a rates table.

Any ideas on how to approach this?

Thank you.