The Midland GXT1000 is a GMRS radios primarily sold in the US. The reason it is difficult to determine what your Cobra radios are is because the model number you provided doesn’t seem to match any known Cobra radios, at least here in North America. Is it possible your model is a Cobra MicroTalk MT850?
If so, that is a PMR446 radio manufactured for use only in the EU. This would explain why the GXT1000 radios won’t talk the Cobras. Although some of the frequencies are the same, others are not. Also, one or both of these radios may or may not be legal for use in some countries, depending on where you are and where you plan to travel. Some countries don’t care, but others do, so you want to research this before using them. We recently produced a podcast on the topic that may help.