Endonucleolytic cleavage to separate a pre-SSU-rRNA from a pre-LSU-rRNA originally produced as a tricistronic rRNA transcript that contains the Small Subunit (SSU) rRNA, the Large Subunit (LSU) rRNA, and the 5S rRNA, in that order, from 5' to 3' along the primary transcript. Note that the use of the word tricistronic refers only to the number of mature rRNA molecules which will be produced from the primary transcript and ignores tRNAs that may also be present within the primary transcript.