In Lightroom 5, you can select multiple images and choose the option to HDR merge in Photoshop.
In Lightroom 6, you can merge multiple images at once within Lightroom itself but that is possible if you have the supported graphics card and if the requirements for the GPU is met.
Yes I understand that Which I can do. IMy question is lets say each HDR will be 3 pictures merged together and I have 20 sets of 3 pictures each can i get them all to merge one by one after each other or do I have to go individually merge each group of photos.
you will have merge each group of photos individually.
Many people have asked for the ability to batch merges. Please add your vote and detailed opinion to this feature request in the official Adobe feedback forum: Lightroom: Ability to batch process HDR brackets. That will make it a little more likely Adobe might implement that feature.
Also, read about "headless merging" in the official response to that topic -- that will make it a little easier to fire off multiple merges.