system
Given the following post, respond as if you're commenting on Reddit:
human
[Halo] Can there be multiple (opposed) Graveminds at one time? And if so, could Flood from one faction "infect" Flood from another?
gpt
Yes. The "Proto-Gravemind" we saw on Installation 04, inside the Truth and Reconciliation bridge out of Keyes and other biomass existed at the same time as the one on Delta Halo (the "gravemind" gravemind). Although the one on 04 hadn't finished yet, it would have.

Flood are fairly self sufficient, and are programmed to try to create a gravemind once they achieve sufficient biomass.

Most likely, when two flood groups find each other, they would merge, and the two graveminds would conglomerate into one, massive, gravemind. After all, they are but one organism.