DIFFICULT - Returning Two Most Recent Records On One Form Line

Hi,

This is a toughie (i think so anyway!). I'll attempt to explain!!!

I start with a CONTINUOUS form in my DB that shows all readings for a single given customer's connections. E.g. Customer A has 5 connections and each connection has say 3 readings. Thus this query which uses joins between the Customers, Connections, and Readings tables, would return a list of all readings for each connection, so in the above example: 1*5*3 = 15 records.

Not too tricky so far, but then what I want is for each connection to have just one line showing the latest reading (easily achieved by use of SQL Aggregate Max function on the date field coming from the readings table) TOGETHER WITH the last-but-one (next most recent) reading. So back to the example taking Customer A's connection 1, the row would be as follows:

Cust Conn CurReading PrevReading
A 1 750 500

Where the CurReading value (750) comes from a different record than PrevReading (500).

I've tried all sorts of ways (subqueries etc.) to achieve this without success. The main problem being that any sub query would require parameters from the current record's fields, which seems not to be possible. Can anyone help or is this simply not possible in MSAccess Forms. If it isn't possible anyone have any suggestions as to an alternative way?

Thanks

Darren