ConnectWise Manage is one that I have the most experience with and it does this. Its been a while but I believe SpiceWorks did this too.
It would be nice to have the option to configure how tickets can be merged more granularly but even the ability to toggle "merge same subject line" or "merge same ticket #" would be an improvement.
So that for instance, if a series of automated tasks complete over night and send an email notification, they could be organized into a single ticket. Makes for less manual sorting.
I'd appreciate it anyway.