Then instead of making a double post the program it gathers the 2 together, merges them with a further time on the second being posted, or third, four of fifth message.
I know about this feature, but I personally do not support it (and also it's not supported in my software). The main reason is that when there is certain amount of messages posted, this helps to eliminate spamming/flooding visitors trying to create too many messages at one session; but if their messages are being merged into another one big message, with the current DB structure this makes the tracking of messages amount impossible. On another hand, there is a limitation on the message size, and it should be taken into attention when merging two messages. Sooner or later, this limitation exhausts and should be controlled somehow. All this makes an obviously «simple» feature like pain.
Maybe you could make a small plugin that could do it, it is very neat.
I could code almost everything in terms of our paid support
and specially for your forum.