In some cases, you can prefer to share a same Workflow with different Projects, and incorporate a small delta based on the current project.
This condition allows the transition if the current project matches with the selected project.
It is not the best practice in JIRA Administration, but it can minimize effort during the implementation of a new configuration.
Add the Condition
Select the Project Condition ...
Edit and View Parameters
Specify the expected Project,
Ok it is defined ... Now the transition is allowed only if current Issue is in the Project Test
The Condition configuration may be done in XML in Workflow descriptor as follow :
Here the condition is valid, if the Required Project Id matches with current project ...