G'day Vinod (?took a guess at your name!),
I would look at using an Array structure in Plex - but be aware this may be implemented so that it pages to local disk depending on how memory is managed on the local computer.
Are you generating for C++ or C# or Java? I think will determine how best to approach the problem.
I use a lot of Source in WinC++ apps generated from Plex to do something similar to manage large objects locally.
Regards,
Darryl