Create a dependent drop down list with dynamic list

Hi

I need to create a 2-stage dependent drop down list.

Stage 1:
In cell G7 (on a tab called 'Data'), I have created a drop down list based on a range name called 'Region' - no help needed here

Stage 2:
In cell G8, I need to create a drop down list which is dependent on the value chosen in G7.

Problem is, I will need to create a dynamic range name here which needs to vlookup or match the value from G7 in a dynamic list of data (the data is on different tab called 'RCA Data' and is spread over columns A:E with row A for headings - the data will go down an undetermined number of rows)

Every time the value in G7 matches a value in the 'RCA data' (the potential matches are stored in column D) I need the corresponding cell value in column C to be added to the dynamic list. This list then needs to be available to choose from a drop down list in G8.

Thanks

If absoluteley necessary, I can switch around the columns so that vlookup works to the right (i.e. searches to column E from D instead of C from D) because I know there are problems searching left of a match