Verify that there is at least one response before a new loop in repeat group

Hi, I'm new to using ODK. I would appreciate it if you can help me with the following problem. In a repetition group that has two questions, I need only a new loop to be started, if at least one of the two questions has an answer. In this case the questions are the entry of a geopunto and / or a photo.
I tried calculating the length of both questions, so if it is greater than zero it is OK, and if not, I get an error and ask that one of the two questions be answered. But it's not working. I attach the example
repeat_validate.xlsx (12.2 KB)

Hello again. There I found two ways to do what I needed. I share it in case someone is interested.
As you will see I had to add a NOTE type question to carry out the verification and this, unfortunately, appears on the screen.
I tried to do the same verification in the geopoint and photo questions but without success.
If someone comes up with a better way to do it, comment on itrepeat_validate.xlsx (13.3 KB)