ACPAP:ACDNUM=4 should be 0 and on extension ADC dig=1 must not be 2, this allows calls on ODN when ADN busy and other way round. You cannot park calls the way you want to in the ACD groups, it is not a function of ACD to do this way, you may be able to transfer to your ODN and hold there to free up the ADN for ACD maybe?
best parnum