how do you get the usergroups of a particular userid?

[souperman]

I'm doing a cron job and want to process something based on the usergroups of a user.

example:

If userid belongs to usergroup 10, or 15, or 20
do this
end if

The cron job calls vbulletin's global file, so instead of me running extra queries and writing my own functions, does vb has something build-in?

I know you can pass an array of usergroups IDs to a function and will return true if user belongs to the any of the groups in the array, but I think that only works for the current user only. Since I running a cron job I'm going to have to pass the userid and the usergroups IDs into the function. Does vb have a function like this? thanks!