I went to Mycroft Holmes suggested site and after awhile I finally built something that worked. I posted the solution below for reference to anyone else who needs help on this issue.
using (var context = new iomniEntities())
{
List<locationGroup> lLG = new List<locationGroup>();
lLG = (from lG in context.locationGroups
join l in context.locations on lG.locationGroupID equals l.locationGroup
join lR in context.locationRegions on l.region equals lR.regionID
where (l.locationTypeID == 9 || l.locationTypeID == 11) && l.active == true && lR.regionID == locationRegion.regionID
select lG).Distinct().ToList<locationGroup>();
return lLG;
}