Hi , I am not sure about attributes related to msend you might to check for that , but then if you are using Advanced Alert Manager
You can add 2 entries on your Alert Trigger Action - Add new action "Execute an external program", that would still achieve the same result you are looking for
First entry - C:\PROGRA~2\PROACT~1\Agent\server\bin\msend.exe -n CXXXXXPAS0029 -a EVENT -m "${Message}" -r CRITICAL...................
Second entry - C:\PROGRA~2\PROACT~1\Agent\server\bin\msend.exe -n CXXXXXPAS0028 -a EVENT -m "${Message}" -r CRITICAL...................
Except for the server name everything would remain the same
Hope it helps