Organization A appears in "My organizations" in your Team Site left sidebar because Organization A is using TeamSideline for online player registration. The TeamSideline online registration process enables an automatic linkage between Organization A and the Team Sites created by Organization A.
If Organization B is not using TeamSideline for registration, then Organization B will not appear in the My Organizations list. The good news is that you can click "Create Team" within your Team Site web site area to create team sites for teams you are part of with Organization B, but Organization B will not appear in your left sidebar because there was no process to create that linkage.
Have more questions? Submit a request