When did the [spoilers] meet back up?

Nomai. When did the crashed nomai shuttles recommunicate with eachother? Obviously the two surviving pods each build one of the two cities on their crash site, but early crash logs in the game indicate that they weren't sure what had happened to the other, but Solanum was born and raised on Ember twin but was educated on Brittle Hollow, clearly indicating by the later generations that they had re-established communication. Is there any indicator of when recom was made? And as a side note, how were nomai able to travel pre-teleporter? We don't see any ships beyond the grounded escape pods & vessel