Spiritbonding Affected by Group Size?

[Ashkendor]

as far as I remember, SB gain is divided in the party, either it is formed with other players or your chocobo.

I can't see this being the case, or those 8 person parties in Urth's Gift would actually be pretty dang slow.

I've never noticed a difference in sb'ing with my choco out or in a party with 1-2 other players.