When you want having multiple domains for same niche, but several services you offer and avoiding 1.1 content, then you should have different content on each domain. Like you have 6 multiple lsi keywords on one big pillar content, spread it through 6 different domains, this is the only way I know to prevent getting double content penalty.
Or spread these 6 lsi keywords through multiple subdomains, or have all on your root domain with category pages, remind category pages are great but it would be hard to rank for broad keywords like sport, marketing, etc,etc you get the idea. The same with lsi pillar content and having multiple domains based on your lsi keyword list.