Problem with the self created Edmx file

Hi

   I have created an edmx file,with <association> and <Navigation> tags.But I have got multiple different datasets ,and a field which takes values from all these data sets.Is it not possible to add those different datasets in the same association and navigation tags.Attached below images shows the corresponding "Navigation" and "Association" of the datasets:-

The Above ,relates only two datasets: "InventoryData" and "DealersInfo" only. But apart from this I have other datasets also, which needs to be used in the same edmx files. What are the syntax for that,cant we use them in the "Association" and "Navigation entries?