My solution (Guides -> List of Guid):

List<tstTest> tsts = new List<tstTest>();

for(int i = 0; i < Math.Ceiling((double)Guides.Count / 2000); i++)

{

    tsts.AddRange(dc.tstTests.Where(x => Guides.Skip(i * 2000).Take(2000).Contains(x.tstGuid)));

}

this.DataContext = tsts;