Schedule on a Crash Course

__________________________________________________
I am facing a ministry dilemma. My dilemma is this, I believe in and am committed to expositional preaching/teaching; not only expositional preaching, but preferably sequential expositional preaching; line upon line, precept upon precept, verse by verse, thought by thought through the writings of Scripture. What does all this have to do with my dilemma? This...

Recently, at the prison where I minister, there have been significant scheduling changes. These changes have divided the entire population into three groups for all activities (chow, rec, religious services, commissary, school, etc). These three groups have religious services on a rotating schedule week by week. One week group one will have services Sun 10 am and Wed 7 pm. The next week group 2 has that schedule and group one has services Sun 2 pm and Thur 7 pm. The next week group 3 has the first schedule, group two the second schedule and group one has services Sat 2 pm and Tue 7 pm.

My ministry team has two services a month. Our service schedule is the second Saturday at 2 pm and the third Thursday at 7 pm. Here's the dilemma, two services, three groups. In any given month, because of their schedule, I'll minister to two of the three groups. On the next month I'll minister to one of the groups from the previous month and the third group. Add to this confusion a fifth Thursday (or a fifth Saturday) and suddenly I've seen one group twice before seeing another of the groups again.

My question is this, how does one maintain consistency of sequential exposition to any (and all) given group within the chaos of that particular service schedule?
__________________________________________________