"fromsymbol @separator" object inable to cope with lot of data

Hello, I've been working with Max Msp for quite a while now but on this simple patch I'm having some issues. I am currently using Max 6.1.10.

So I'm receiving from the serial port (Arduino to be precise) a flow of data that I'm trying to sort out with the fromsymbol @separator object. The data coming out of the serial port is formatted in this way: "AA111 AB111... etc BA111 BB111etc...".
With the fromsymbol object I would like to let only the selected value pass in order to have perfect control of the single sensors (the data comes from 80 light sensors).
If I try to use the from symbol object on it's own on a patch it works like a charm, but as soon as I use it in my patch it seems it's not able to cope with the amount of data and even if every fromsymbol is able to send the correct value through displaying it on the integer number under, it sends also all the other variables which the int number doesn't understand causing a stack flow of errors that sometimes make the patch crash.
Somebody has a workaround, or a solution?

Thanks in advance.