How To Auto Increment An Alphanumeric Primary Key In SQL? :(

 How to auto increment an alphanumeric Primary Key in SQL? :( Because I want to add something like this in the Primary Key, for example i'll add a new data with an alphanumeric value of ABC-0001, then I'll add another 1, and it auto increments to ABC-0002 and so on.. How can I do it? And if I'll add a new alpha character in the Primary Key field, for example DEF-0001, then I'll add another and it auto increments to 002, and so on, and it will go back to 0001 if i'll use another combination of alpha characters. for example, i'll add a new alpha character AAA, will it go back to 0001 or it will continue?
 
T___T I hope u get my point.. I want my table to look like this if i have added the data

ABC-0001
ABC-0002
DEF-0001
DEF-0002
AAA-0001

then if il add a new 1, for example ABC
it will auto increment to 0003 in the same field, it will look like this after adding

ABC-0001
ABC-0002
ABC-0003
DEF-0001
DEF-0002
AAA-0001

Will it be possible? :(