It's pretty common to put multiple organs from the same animal in one block, and develop a legend so an entire study or trial has the same embedding scheme for each animal. This makes it easier for the pathologist as well as the tech if the slides for all the animals are similar. It also benefits your QA. I don't know if there's an industry standard, but try to put similar 'consistencies' of tissue in each block - kidneys and adrenals go together well, as do liver/spleen/pancreas - - intestine and stomach - - -lungs/heart/esophagus/trachea. Orientation of the organs is a key factor, i.e., orient the larger pieces in the block before the smaller ones so you can entirely face the larger organ without risking losing the smaller one.
Jacqueline M. O'Connor HT(ASCP)
Global Pharmaceutical Research and Development
Recently, our lab have to trimming 40 organs per rat for general toxic studies. Our Pathologist do not mind read two or three organs in one slide such as embedding adrenals and kidneys in one block. I wander any lab has done that. Do you have a scheme that I can reference for. Thank you very much.