Hmmm. This is challenging. The easiest out of the box thing I could think of for exactly what you asked is to create the appropriate layouts and manually schedule the occurrences monthly or biweekly to accommodate the coming schedule. There are recurrences in Xibo, but the need to omit certain days is not something I’ve seen that could be accommodated easily.
Finally, the easiest, but it’s not exactly what you asked for but you could also just accommodate both A/B patterns on a single layout, but have an element of the layout be a monthly/weekly calendar identifying what days are what pattern.
Ultimately you can do exactly what you want, just not out of the box with the way your schedule goes. I’d toss this to the Xibo team as a feature request – the ability to ‘schedule a schedule’ – basically have a full day’s schedule that could be set to run on a series of days as opposed to either one day or an inflexible recurrence.