How to link tasks in different Redmine projects?

Question

Project management

For example, there are projects:
Project A:
Task 1
Subtask 1.1
Subtask 1.2
Task 2
Task 3
Project B
Task 3
Task 4
For example, that Task 3 could be carried out simultaneously in two projects in any way?
There are regular tools that allow you to fix links between tasks in only one project. But there are situations when it is necessary to link tasks in different projects, but not to duplicate them.
Thanks

Answer 1

when you need to link tasks in different projects, but not to duplicate them.

What does it mean to link but not duplicate? If it suits you that task 3 can have different numbers (that is, the entities will be different), then there are no problems, only linking between projects needs to be allowed.
Or I did not understand the essence of the question.

Answer 2

there are no regular ones, it is possible through plugins, look for the same question on the toaster, there was a link to a paid module for this.