Multiple net names in Altium Designer
The best way to do this in Altium is to use Net Ties. These will join two separate nets. See:
https://www.smtnet.com/library/files/upload/NetTies-and-How-to-Use-Them.pdf 

I will also occasionally use zero-ohm resistors to accomplish the same goal if there is a chance that I may need to break the connection to help troubleshoot an issue.