[MM3-users] Importing MBOX from custom listserv to MM3?

We are looking at moving from a home grown listserv system at a client to potentially MailMan3 for the lists platform instead.

We have historic thread data from the homegrown systems in mbox form. Is there a way to import that into MM3 for indexing in the archiver there so we dont need to keep the (literally massive) MBOX file?

Sent from my Galaxy