There are to be two separate services in Omagh this weekend on the tenth anniversary of the bomb attack in which 29 people including a woman expecting twins died.
Relatives of some of the victims have organised their own tribute on Sunday and will not be at the civic service on Friday, but local clergy say they will now attend both.
A number of the Omagh relatives including Michael Gallagher, whose son Aiden was killed in the bomb, are unhappy with the council's handling of the creation of new memorials in the town.
There was contention over retaining the wording of a previous memorial stating that the victims were 'murdered by a dissident republican terrorist car bomb'.
This has now been inscribed on part of the new memorial following the recommendation of an independent team.
But the delay and public wrangling has annoyed Mr Gallagher and some other relatives.
They will not be present at Friday's civic ceremony when a new memorial and garden will be opened on the tenth anniversary of the attack.
Former Lebanon hostage Terry Waite will also give an address.
Meanwhile clergy from the town's main churches have agreed they will now attend both the council-organised service and the one on Sunday run by the Omagh support group.
Church leaders initially rejected an invitation from the victims' families who are organising it.
They had originally stated that they would only be attending a service organised by Omagh District Council on Friday, the date of the Real IRA bomb.
The family-run Omagh Support and Self Help group, which is organising the Sunday event, had heavily criticised the clergy for turning down its invite.
Representatives from the town's Presbyterian, Methodist, Church of Ireland and Catholic churches changed their stance after meeting last night to discuss the issue.
In lieu of the four clergymen, the support group had asked a British Army padre based at Ballykinlar, Co Down and an Omagh-born Catholic priest who now ministers in Wales to officiate at their service on Sunday.
The town's church leaders will now join them at the ceremony.