Does any of you have experience in having two different environments in HP SD. We have one running on HP SD4.5sp8 one Oracle DB and another system HP SD4.5sp14 on another Oracle DB. Is it in any way possible to "share" calls or somehow let rules update the link between a call created in One system and the other system?.
Yes it is possible. I have implemented an interconnection between Oracle CRM and Service Desk for ticket exchanging. It was rather easy, and since at your case both platforms are SD it would be more easier.
Since SP8 it is possible to update data from and to an external system. What I did was every time a ticket was created I used the "update data from an external system" in order to pass attributes to a servlet. The servlet transformed the received data to an xml and posted it to Oracle's side.
This would be easier between two SD servers since the xml is the same and no data transformation is needed.
If you have some programmer with knowledge on SD web api you won't need the indermediate xml. If not, create an xml (and the corresponding import mapping), extract the data from the source (or use servlet to create the appropriate xml) and then import the data to the other Service Desk server.
Of course some things must be taken under consideration, for example the service calls cannot have the same id on both systems.