Arduino and Interrupts: Fast way to get pin values
I have a first solution myself, but i could not test the reliability as the hardware is not finished jet.

First I added oldPins and tickCount as global variables:

static byte oldPins = 0;
volatile unsigned int tickCount[4] = { 0, 0, 0, 0 };


And thats how I solved the ISR at the moment. Better solutions are more than welcome.

ISR( PCINT2_vect ) {
  //Read values from digital pins 2 to 7
  const byte actPins = PIND;
  //Match this values agaist the oldPins bitmask (XOR and AND for raising edge)
  const byte setPins = (oldPins ^ actPins) &amp; actPins;

  if (setPins &amp; 0b00000100)
    tickCount[0]++;
  if (setPins &amp; 0b00001000)
    tickCount[1]++;
  if (setPins &amp; 0b00010000)
    tickCount[2]++;
  if (setPins &amp; 0b00100000)
    tickCount[3]++;

  oldPins = actPins;
}