Nashoba Valley -- There are six towns, five parishes and three priests.

The three pastors, Father Edmond M. Derosier, Father Paul L. Ring, and Father Shawn W. Allen, work together as part of the Nashoba Valley cluster, formed, in part, as a response to the priest shortage in the Archdiocese of Boston.

This arrangement is unique in two ways. It’s a large rural region spread out over 140 square miles. And it’s far removed -- geographically -- from the archdiocese.

The cluster, which consists of Ashby, Ayer, Groton, Pepperell, Shirley and Townsend is located at the far northwestern end of the archdiocese and bordered to the south by the Worcester Diocese. The Manchester Diocese lies just across the New Hampshire state line. Only three towns separate Ashby, the most far-flung community, from the Springfield Diocese.

The Nashoba cluster cuts deep into Central Massachusetts. So, a casual observer might conclude this bucolic land with rolling, cow-dotted hills is part of a neighboring see.

Father Ring is pastor of St. Joseph Parish in Pepperell and Sacred Heart-St. James Parish in Groton. “Are you still in the diocese?” is a question he has heard more than once, typically from his lay friends.

“Some will joke and some honestly aren’t sure,” he explained.

“It’s closer to Worcester than it is to Boston,” he said of the Nashoba cluster.

Father Derosier, pastor of St. Anthony of Padua Parish in Shirley and St. Mary Parish in Ayer, said the present arrangement is the result of 18 months of planning, which ended in 2006. Decisions were made by a 35-member committee comprised of people from each of the five parishes.

One factor taken into account was the region’s largely rural nature. A future housing boom could greatly increase the population, so keeping the churches open was a priority, according to Father Derosier.

The three priests assigned to this territory cover for one another during a normal week. This involves a complex mix of scheduling Masses, sick calls and hospital visits. It’s a schedule they’ve been juggling for the past year and a half, ever since another pastor retired from St. Mary’s.

Technology helps.

“Every priest in this cluster has a GPS unit in his car,” stated Father Derosier, explaining that the satellite mapping system is needed for geographical guidance along the region’s miles of country roads.

“I can very easily get a call in Ashby, which can easily be 15 miles away,” he said. “It’s one of the great technological advances.”

Father Derosier said he and the other priests assigned to the Nashoba cluster decided they needed these devices--as they’d be making sick calls for one another-- after realizing, “Wait a minute -- we could very easily get lost.”

The three priests carry cell phones and beepers as well.

Father Ring relies upon a Palm Pilot electronic organizer to keep track of his schedule as he travels between parishes. Residing in the Pepperell rectory, he keeps his main office in neighboring Groton.

Although he’s running “two, separate and distinct” parishes, he said he needs to have just one schedule, and this is where his electronic organizer becomes indispensable.

“I try to be fair and balanced with my time,” he said, adding that all his parishioners need, and expect, a full-time priest. “They consider me their pastor -- not half a pastor.”

Without his electronic organizer, Father Ring said he could run into conflicts scheduling weddings, if one wedding book was in Pepperell and another was in Groton. Having this information at his fingertips prevents embarrassing mistakes -- and excess shuttling between parishes.

“I always have to be aware of what my schedule will be,” said Father Ring. “I have to be very aware of what’s going on in the other parish.”

Even knowing where to be for weekend Masses can be tricky. Daily Masses, as well as the 4 p.m. vigil Mass, are in Pepperell. On Sunday, Father Ring says a 7:30 a.m. Mass in Groton. And he and Father Allen, pastor of St. John the Evangelist Parish in Townsend, trade off for the two 9 a.m. Sunday Masses, one in Pepperell and the other in Groton. Father Ring also celebrates a 5:30 p.m. Mass in Groton.

“Believe me, it took awhile for me to get my hands around it, and I still get confused occasionally,” he stated.

All three priests celebrate four Masses each weekend, one on Saturday and three on Sunday. Father Ring said special dispensation was needed for this.

“I’m busier than I used to be as a parochial vicar,” said Father Ring of his former assignment at St. Mark Parish in Dorchester. “But I’m not as