PTC Integrity Cli: need a particular commandline

Hello,

I have a Project with a structure like:

+project

| file_1

|file_2

|+sub_project_1

|file_1_1

etc...

|+sub_project_2

|file_2_1

etc...

when i create a sandbox of the whole project and then try to (resynchronize or check_in) only the sub_project_1 or the sub_project_2, an error message is displayed saying that this project/sandbox is not registred.

any help to fix this issue? For me is the best way to create a sandbox of the whole project but each time i need to resynchronize/check_ii/check-out each sub project separatly ? And it is very hard to create any time for a subproject a new sandbox.

Any method that allows to register automatically the created sandbox with its subprojects?

Thank you in advance

regards

Miled