Are asking if it is acceptable to have the outputs of one stage box feed the inputs of another stage box gain additional length? Or are "sub" (drum, keyboard etc.) snakes feeding in to the main snake?
Either way it is acceptable. It really shouldn't matter as long as the cables and connectors are working correctly. It is like extending a mic cable by plugging in another cable.
Ideally, it would be better to have a cable the correct length without additional connections (which could be subject to dirt and corrosion), but mic cables get extended all the time with good results.