Multiple Project float

Hi all

We have multiple project each broken down into froont end stuff (Design, procurement etc) and manufacture. Because completion relies on the same machinery/ processes each project is linke to the next so we have a schedule of work running through the factory.

Thinking aloud

Given that each project has a different contractual completion date. All projects front end float then becomes reliant on the progress and achievement through the factory and each projects completion date. This can mean that some projects have negative float because of links to other projects. To me this is "false float", how do I prioritise and/or level Enginerring activty resource and ignore his issue.