Selecting a random household member! Can anyone help with the following task

You must complete the following questionnaire
Tourism questtionaire
Then there are 4 more sections (roster), only for one of the members of the household who will be randomly selected, depending on how he filled out 1 section (screenshot above). For example, if there are 2 people in the household who have had domestic trips (the first has 3 and the second has 5, for a total of 8). then in the program in the range from 1 to 8 it will select a random number. This will be suppose 2 (the second trip of the first household member) therefore, to complete the second section, it is necessary to select the first respondent and interview on his second trip. I cannot pass to the roster (section 2) the name of the respondent to be polled. Thank you in advance for your help

Hi to everyone!
Is it possible for me to display the names of the respondents in another section inside a static text with the number of overnight stays For example. %rostertitle% had %overnight% trips

I tried to sum the trips of the respondents and get a random trip number from this range. I succeeded in all this, but I can’t bring it to the next roster. That is, I managed to get a random trip number, but I can’t identify a member of the household from it. And most likely, I should have chosen a random member of the household among those who had a trip (trips>0). I would be very grateful for the help!