ada drive numbering

Hello.

I've got a 13.4 box with three SSD and one HDD.
Usually the SSDs are ada0-ada2 and the HDD is ada3.
However, from time to time, at boot, HDD becomes ada2 and one SSD 
becomes ada3.

This is annoying and I'd like to avoid it.
Is there any way to achieve this?

Of course I've searched, but everyone seems to suggest I use labels 
instead of plain device nodes.
While this makes sense, it does not solve everything, as some scripts 
are not under my control (e.g. Nagios on another machine that checks 
ada2 for remaining life).

Thanks in advance.

  bye
	av.