When they met the Northern Secretary in Belfast yesterday the Relatives for Justice group got a sneak preview of what is likely to be a contentious element of the "take-it-or-leave-it" British-Irish package designed to break the deadlock.
The line from Sinn Fein in recent months is that it would not be able to sell to its constituency proposals that did not contain a ban on plastic bullets.
Dr John Reid told Relatives for Justice that a ban was not possible at this stage but that recruits to the Police Service of Northern Ireland would not be trained in their use, at least in the first couple of years of their service.
In the meantime the British government would engage in intensive efforts to find an alternative to plastic bullets.
Sinn Fein has insisted it could not advise any nationalist to join a force where police officers might have to fire plastic bullets at members of their community. As the governments view it, nationalists might join the force if they do not have to use the plastic baton rounds.
Mr Mark Thompson, of Relatives for Justice, told Dr Reid that this compromise was insufficient: plastic bullets had to go, it was as simple as that.
But this proposal is an indicator of the "creative thinking" that British and Irish officials have put into devising a formula that the Ulster Unionist Party, Sinn Fein, the SDLP and the smaller Yes parties will find difficult to reject.
Other likely elements of the package are beginning to emerge. These include:
Indemnity against conviction for the estimated 60 loyalist but mainly republican paramilitaries "on the run".
Former republican and loyalist paramilitaries eligible to join District Policing Partnerships, which at local level liaise with the police.
An international judge, invested with some investigatory powers, to decide on the merits of holding inquiries into the killings of Pat Finucane, Rosemary Nelson and Robert Hamill.
As a quid quo pro for unionists the same judge to decide on the merits of holding inquiries into allegations of Garda collusion with the IRA.
Eight members, rather than the higher simple majority of the 19 members of the Policing Board, to decide whether there should be inquiries into police actions that are current. This is an attempt to meet nationalist concerns that the membership of the board could be loaded with those opposed to inquiries. A greater number of members may be required to decide on any inquiries that are retrospective.
Enhanced investigatory powers for the Police Ombudsman.
Powers of the Policing Board to be strengthened.
The RUC name to remain in the "title deeds" of the Police Act but that the Police Service of Northern Ireland title be used for all operational purposes. These to be reviewed if it is judged that attempts were being made to use the RUC name in operational circumstances.
A programme of demilitarisation.
The IRA and loyalist paramilitaries, in conjunction with the Independent International Commission on Decommissioning, to decide how arms verifiably could be put beyond use.
Various of these proposals are difficult for unionists and nationalists but the British and Irish governments are trying to make an offer to the parties that they cannot refuse. Acquiescence rather than acceptance is what they are seeking.
Their document is due to be presented to the Northern pro-agreement parties at the end of this week, most likely on Friday. The Taoiseach, Mr Ahern, and the British Prime Minister, Mr Tony Blair, after their week together in Shropshire, may meet again for the unveiling.
The initial plan was to present the document privately to the parties but the two governments are now seriously considering also releasing it to the press to avoid selective partisan leaking of the proposals by unionists, nationalists and republicans.
It remains unclear what the IRA might do on arms. There has been speculation in Belfast this week that the IRA might issue a statement to coincide roughly with the release of the document.
The purpose of the statement could be to try to provide reassurance to unionists and to Mr David Trimble that, as per its May statement of last year, the IRA would begin a process to verifiably put its arms beyond use.
The IRA has indicated it would only take such action if outstanding issues such as policing, demilitarisation, safeguarding the institutions of the agreement and other matters were dealt with to its satisfaction. Mr Ahern and Mr Blair earnestly hope their package will meet not only the demands of the IRA but those of Sinn Fein,the UUP, the SDLP and the other Yes parties.