Eikon codes for delisted companies

I'm trying to write a script to download data of delisted companies from Eikon. I have tickers of these companies, so the first step would to create the RIC, which in the case of delisting also includes a suffix of the type ^B19 (where 19 would be the year of the delisting). I have delisting dates, so the digit part is not a problem but the letter seems to be a bit random, e.g. for a company delisted in 2018 it was ^H18...

Does anyone know if there is any logic to this and if it's possible to reconstruct the "delisted RIC" from ticker and delisting date?