Technically, your children need to have a primary residence in the school district they attend. I'm not endorsing this, but people have used a family member or friend's address if they are in the desired school district.
The official position of most school districts is for their students to live within the attendance zones. However, most of them will allow transfer students provided the proper procedures and guidelines are followed. Sometimes, it doesn't even matter where your primary residence is.
I would contact RRISD administration for the most accurate response.
Their number is 512-464-5000
Of course, you would be responsible for all transportation.