Not sure if this is what is happening, but if you disable Group 2 and that is the only Group active, you will have to be scanning the System in order to activate a Group in it. Always try to enable a Group before you disable a different Group. That way you will not 'lock yourself out' of it.
I would recommend changing it to different Systems if these are all Conventional channels then activate them using the Quick Key numbers. (# for on/off without FUNC first) If you have only a few Groups, that would be more efficient.