You can either have multiple portals all linked to each other.

Or you can make 1 main portal in your base and a second portal purely for exploration. On your map you make markers with portal names so that you can use your main portal to go to other portals by renaming it. This cuts down on resources and having a large room full of portals.

Just make sure that portals are in safe locations and when exploring to put down a portal very quickly in case you die.