Wrestling's first real "brand extension" may have been in spring through fall of 1985, when JCP had a Carolinas universe in syndication/on local TV and an Atlanta universe on TBS, and they were kept mostly separate.
Flair's initial chief rival on TBS was Magnum TA and they were headlining Omni house shows and doing spot shows in other territories around the country. In Carolinas it was all Nikita as they built to first Bash, which drew 27,000 fans.
Atlanta TV was mostly used to get the Midnight Express over. Carolinas TV was mostly used to get the Rock N Roll Express over.
The converge happened after the late September Omni show, when Flair finally became a real heel for good by turning on Dusty in the cage.