Let players build adjacent to the main colony without using a land claim if certain conditions are met.  

Restrict it to the buildings that are typically built there, like patents, upgraders, hackers, off world launchers.

The main colony is happy to provide some of their land for development.  They benefit from the jobs created.  Perhaps they want ongoing lease payments as compensation.  Perhaps they are selective in who they trust and expect certain conditions to be met like an HQ level requirement or an A bond rating.