php if user group

[Flyte]

i am trying to write a php statement but do not know what variable to call
I only want the photos to display if they are in the photographer user group.

this is what I want, but dont know what to put in the parenthesis

if (usergroup photograhper) {
do this..
}
else {
do nothing
}

I don't want the users to be in the usergroup photographer, I only want photographers photos to be displaying in my image viewer.

Thanks!