one advice for two orders

We plan to develop a local solution for so called SWITCH trades using SEC.OPEN.ORDER and SEC.TRADE.

With a SWITCH you move your assets from one fund to another within the same company on special conditions. We want to have one order resulting in a buy and sell trade.
To make this a look better for the clients we would like to combine the BUY and SELL in one advice.

Has anybody designed something like this?
Any better idea than suppressing one advice and manipulating the other during mapping/printing?