Time Machine and Wifi

Hi,

Is there a way I can change settings for Time Machine to backup regarding wifi it connects to?

Scenario is this: We have 3 different wifi connections/options. I stay on 1 all the time. But Time Machine with Time Capsule is somehow set to backup to a different wifi. For some reason it will not switch to the one it is set up to and so I continuously receive warnings that I "Time Machine has not backed up in x mount of days". I can not see a setting to change wifi. Nor do I understand how to do this with Time Capsule if that is the issue.

Please assist.