Not exactly what you want but you could create Presets to do some of it. You would first need to select the images you want Preset A to be applied to then Apply the Preset. You can use the Filter Bar to help with the selecting of specific images.
LR doesn't have actions like Photoshop and other applications, unfortunately. It does have a mechanism to write plugins, but that requires a high level of technical expertise.
To build on Just Shoot Me's reply, the best you can do is to use the various preset and search mechanisms to speed up the individual steps of your workflow. It sounds like you are already using Develop presets, and you're probably already using export presets?
You can use the filter bar or smart collections to search for photos with a particular range of exposures; with either, you can save away frequently used criteria as presets or saved smart collections. The advantage of using the filter bar is that it can be easily applied to the current folder or dumb collection you're working on, whereas that's much more clumsy with smart collections. But the advantage of smart collections in this case is that you can do things like "Shutterspeed is greater than 1/10 sec" easier and more reliably than in the filter bar.