The example you provided is considered running multiple instances of XCP on a single host. One of the main reasons why it is unsupported to run multiple instances, such as multiple SSH sessions, to the same host is because essentially only a single instance of XCP is actually running. The single instance of XCP will encounter "collisions" with one another and can result in severely undesirable results to your data also referred to as "unpredictable" in the documentation to avoid using such stern language.
XCP also only writes to a single log file, so running multiple instances of XCP the log files will be overwritten by each instance and will have missing data to troubleshoot any errors or inconsistencies.
At this time running multiple instances of XCP to the same host is still considered unsupported.