Unfortunately, this is not something that is there by default in the system.
FORTUNATELY, it is pretty easy for a Sys Admin to set up a simple parent/child relationship: Add a new Reference field on the Contract [ast_contract] table called Parent contract that points to the same table. Then you can define Parent contracts.
Because one parent can have many children, you can then add a new related list to show the child contracts of a parent. This is where it may get a little tricky. It is easy to add the related list (Contract -> Parent contract), but the resulting related list needs to be updated to allow you to select Child contracts. Right-click any list header and select Personalize > List Control. Then click the Enable Edit button. This allows you to select already created Contracts as children from a List collector instead of going to each child to select a parent.
