adopting

Adopting wife’s kids

 Assalamo alaykom brother/sister;My name is Hicham, a Moroccan person. Some times ago I met a girl by net and God helped me make her a Muslim. But later on the relation dveloped that we are planning marriage now. I do want that very much going on the paths of our prophet; and I know my future wife has very diificult situation: she has two kids of unmarried marriages. She has two diferent kids with two different "fathers". I still accepet this because I know that turning again to Isalm cleans all the bad history, and my intention is so human that getting this marriage will help more people come to Islam esp her family.Anyway now i need your advice about parenting; I know that it's forbidden to say that someone is a person's son where is he is not in fact. But this is when the marriage is legal and halal.  The situation is different here and the mother is a Muslim now, so -1- it is possible i give my name to the kids.  2-  Can I accept to have the kids as my sons only as officially(only in papers); but legally and in Shri'a, I will not accept that and will all the time tell them am not the dad; and i will always take them to see the true"dad"(who are both addicts to drugs)Is this possible? Especially that this will help us gretly overcome lots of administration and bureacratique problems .In addition it may help make the kids more secured psychologically.the most important thi,g in all this  is that i will abide by what Islam states even if it say no.I should be very grateful if you could or even could not help  for we are all brothers. And i love you in Islam.Assalamo alykom