How To Append Sequential Number To A Text String To Avoid Duplicates

Is there a formula that will add a number, in sequence, to the end of a text string to avoid duplicates?

I need to generate an ID number for transactions. This ID number is the Account Code-Last Two #s of the Year-Unique 3-Digit Number. So for instance, 5022-14-001 means it is the first transaction from account 5022 in the year 2014.

Column A has the Account Codes. Column B has the date of the transaction in MM/DD/YYYY format. So far the formula I have is:

=CONCATENATE(A1,"-",RIGHT(YEAR(B2),2),"-",TEXT(????,"000"))

With ???? being some function or set of nesting functions I need to create the sequential number. It needs to be able to say "Okay, this is the third instance of there being a 5022-14, so we need to stick -003 at the end of this."

Additionally, this "003" needs to be frozen, so if we change how the sheet is sorted and the line item moves around, it will still always be "003".