World comp + world creator and importing parts?

wondering if their is a guide or info on importing parts of heightmaps or sections using world creator into world comp. This way I could work on sections and export smaller sections of a larger world to make my life easier.

Using world comp + world rebiasing. Getting tired of exporting a 30,000m by 30,000m map over and over trying to correct sections. Would be allot easier if I could just make smaller maps then export those vs waiting two days per “attempt.”