Yes, if you have the multicalender available: by creating houserules, to be applied to the specific periods, with proper "lenght of stay" and "check-in/out days" set..
But check-in/out times(!) can not be set, only defaults from the listing apply.
Or by making custom settings for specific periods in the "availibiliy" section (but limited to "lenght-of-stay" and "check-in day" only)
We attempted to do what you proposed prior to reading this conversation and thought we had it all figured out. Then when using our computer, we saw that only Saturdays appeared as "opened" on our calendar with the next six days "blocked off". If a potential guest clicked a Saturday, it did inform the potential guest that we had a seven day minimum (and seven day maximum with the ability to manually add on days upon request). But from a visual standpoint, again, it looked like we only had one night a week open throughout the summer. This same issue did not seem to occur if we were on the AirBnB app; all days throughout the summer appeared open on the app's calendar and it informed potential guests that we had a 7-day requirement. The problem with the app, however, was that it appeared to let guests book any seven days they wanted, not necessarily starting on a Saturday. We are at a loss as to what to do beyond letting people check in any day they want rather than a specific day for their 7-day stay as we don't want people to think our summer is booked except for Saturdays.