Machine time as attribute stored in program group

[nxexplorer]

Hello Experts,
I need help to get attribute of total machine time in program group attribute. For now, I made it by Postprocess all operations in program group, then I can get the total machine time's attribute inside that.

But after experiencing large number of operations, it takes time very long.

What I need is there any simple method to create total machine time's attribute in program group?

Thank you.
Best regards,
Maryadi