199926 Help Me Find IP Addresses

I am not sure if my project is possible for someone to do or not. I have a poker forum, and 3 members have posted my passwords on other forums. The problem is, the other forums will not give me their IP addresses and email addresses so i know who they are and can ban them. I can see everyones IP address in my forum but these 3 people posted in 3 other forums, they are just members of my forum. So what I would like is for someone to go to the other forums and find their IP addresses and email addreses if possible, at least the IP addresses so I can ban them from my forum. The other forums are in english and dutch i think. maybe some other european language. I couldn´t understand two of the forums languages. When you give me their IP addresses I can then look through my members and whoever has the same IP address I can ban. So, can anyone do this for me? I can´t pay much for this, it´s just really annoying and I´d like to get rid of these three dishonest members. If it happens again in the future I will always work with you in this situation. Thanks.