How to set fit range in simultaneous fit?

Dear Root Community,

I was wondering what is the correct way to set a fit range or multiple fit ranges for a simultaneous fit? There are a few post regarding this topic and a page (p.71) dedicated to this in the RooFit User Manual, but I was not able to find a satisfying answer…

I created a minimal working example with 4x4 slices and some constraints:
fitComplete.cpp (11.6 KB)

However when applying a global fit range either the fit or the normalization in the plotting process fails and the results look off.

When trying the fit with individual ranges for each slice I receive an error message that the ranges are overlapping:

ERROR:Integration -- gauss_t0_e0 : integrating with respect to the variables (x) on the ranges  "fitRange_t0_e0,fitRange_t0_e1,..." is not possible because the ranges are overlapping
libc++abi: terminating due to uncaught exception of type std::invalid_argument: gauss_t0_e0 : integrating with respect to the variables (x) on the ranges  "fitRange_t0_e0,fitRange_t0_e1,..." is not possible because the ranges are overlapping

Is there a working example or tutorial where this is successfully done?

Best Regards,
Adrian