MODIFIED: Is it advisable to group two (or more) GPIO out pin to obtain more mA?

[flavigny]

Hello,
I have to drive external load at 3V, 24 mA.
In the design, I will insert an Uln2803 driver.
BTW, is it possible to simply use more than one GPIO pin ?

I dream about this schema:
[modified to limit current on EACH pin.]
                   (diode)
    GPIOx------>|----(resistor 470 Ohms)----------+
                                                  |
    GPIOy------>|----(resistor 470 Ohms)----------+-(load)--Gnd
                                                  |
    GPIOz------>|----(resistor 470 Ohms)----------+

so, current from each pin is approximatively limited to 7mA.
                   
Does anyone could confirm ?
Regards.
PO.

Post-Scriptum: According to the answer below from Olimex, I read Chapter 37 and table 2.8 in: http://www.freescale.com/files/dsp/doc/ref_manual/IMX23RM.pdf . At this time I have not found the maximum power available.

[olimex]

generally yes, just look in the user manual or datasheet what is the max current which could be sourced from one port group.