Wiktionary
co-host
alt. A joint host alongside another (compare co-star). n. A joint host alongside another (compare co-star). vb. 1 To act as a joint host. 2 (context computing English) To store data on a shared server (as in web hosting).
Usage examples of "co-host".
Terries didn't put up a warm reception for Dauble, but Mendoza's party co-hosted a reception for her with Deseret Space.
SF literature and mainstream America complimented each other like a warm handshake in those years, and it’s no coincidence that Clarke co-hosted CBS’s coverage of the moon landing with Walter Cronkite in 1969.
The International Academy of Astronautics and MIT were co-hosting a press conference in the morning.