<p>I'm printing 6 separate parts in one go, after 4 hours of printing one part failed, but the other 5 are printing nicely.</p>
<p>Is there a way to prevent the print from printing the failed part and continue printing the other 5 parts.</p>
<p>I'm using Cura and an Ender 3 printer.</p>

No, once you sliced the 6 parts on the build plate in your slicer, the G-code is fixed and the printer will print as the sliced instructions. During printing it cannot skip the code of a part that failed along the way; there is no way to interfere with the printing other than stopping the print. For that reason, many people don't pack the build plate too full, the more parts, the higher the chance it fails. You could print the part one after each other. Packing the plate with multiple parts is usually not faster than printing one at a time (if it fails you have nothing, otherwise a single failed print).
Depending on the size of the parts you can also tell the printer to print each part on the plate one after another in a single job; note that the printhead dimensions limit this. If one fails you stop the job, but the already printed parts are saved. You can then commence a new print of cut the G-code and reprint the shortened file.