Separate workplaces with light curtains in safety signs.

I'm a welder robot programmer. I have a security problem what I can not solve. There are two work areas separated by walls and each has one entrance. At the entrances there are light curtains. There are defined spaces for work spaces in the DCS system. The problem is that if the robot welds in one of two space and the other light curtain signal is interrupted then the welding stops (error message: SYST-033 SFSPD signal from UOP is lost). I would like that the process would only stop when someone enter the space where the robot is. I examined the signals in the DCS Safe I / O connection window, the signals are received separately from the two light curves. Please help me!