Imagine a case in which one is invited to volunteer with a group that is preparing and serving a meal at a homeless shelter. The group has decided on a menu that includes milk and meat together in the same "main dish" recipe. The volunteer group as well as the homeless recipients are almost all non-Jews.
In a situation like this, is it OK to participate as a volunteer? Does it matter if the volunteer does not directly work with the meat and milk mixture (e.g. preparing or serving the dessert or salad, instead)?