
As per Jose
Serena Dimensions allows this - In fact you can define your own "Relationship Names" and allow/disallow them between Item Types.
eg
A "sub-prog" type could be related to a "prog" type using a "Called-by" relationship.
A "Application" type could be related to a "Server" type using a "Installed on" relationship.
But you wouldn't have a "Server" "installed on" a "program" etc