rDSN PTR for dedicated server, one shared IP and one dedicated IP

Hello, I am having some questions about my PTR records at dedicated server. This is the idea: We have one shared IP address where we have ~100 web sites. Yesterday we bought another IP address and we are planing to buy a domain, install some newsletter PHP script and to offer it to our customers, after we test it. In my host provider control panel I have options to change rDNS (PTR). Currently it is set as: xxxx.xxxx.xxxx.xxx1 -> server1.mydomain.com xxxx.xxxx.xxxx.xxx2 -> p-xxxx-xxxx-xxxx-xxxx.static.contabo.net I am not sure why is second PTR so different, maybe generic or something. My host provider is Contabo.com. xxx1 is main IP and all accounts are currently on it. xxx2 is new IP where I would put one account, one domain and send newsletter emails (not spam) from it, so if my customers ruin the IP reputation no big deal, because all normal email correspondence would go thru main IP, at least that is what I think. Please correct me I have it wrong. Now my question is: Can we set up two IP to point at our hostname: xxxx.xxxx.xxxx.xxx1 -> server1.mydomain.com xxxx.xxxx.xxxx.xxx2 -> server1.mydomain.com and what would happen if we do it? Will it ruin something? Will it affect email deliverability? We have already enabled sending emails from assigned IP address, tested it, and it works. Sorry if this is stupid question, but we had to learn on our mistakes in past and it was not pleasant. Thank you