You would have to "trick" our software into doing this, followed up by some manual data processing on your part. The trick is to program two different CBC exercises that have exactly the same attributes and levels, but only differ in terms of how many product concepts are shown per screen. Then, you move around the choice tasks in the question list (using the up and down arrows under Write Questionnaire) so that the two CBC exercises are mixed together (for example... Exercise1Task1, Exercise2Task1, Exercise1Task2, Exercise2Task2, etc.)
For analysis (assuming you'll be doing either Latent Class or HB estimation), you would need to export both CBC exercises to either .CHO format or the easier "Single Format .CSV" file. Then, you need to combine the files you exported so that you gather all the choice tasks (from the different exercises) within each respondent. You will need to use the standalone Latent Class or standalone CBC/HB software programs to estimate the utilities, because Lighthouse Studio cannot accept this combined data file.