Three-day conference gets under way in Saudi capital Riyadh without Kurdish groups, which are holding their own meeting.

Saudi Arabia is hosting a three-day meeting in Riyadh to try to unite the Syrian opposition before potential talks with the government of President Bashar al-Assad.

There have been attempts to do this before, but this time international peace efforts are gaining momentum.

There is a need for the opposition to speak in one voice and present a common vision for Syria’s future.

The alliances in this conflict are a complicated maze: There is no clear way through.

There is a spanner in the works already after the decision by Saudi Arabia not to invite the Democratic Union Party (PYD), the largest Kurdish group, and its armed wing, the YPG. Its allies, the Syrian Democratic Forces (SDF), have not been invited either.

Instead, they will be holding a separate meeting in Syria’s northeastern province of Hasakah.

The Saudi meeting comes amid international efforts to restart peace negotiations with the Syrian government and there is a need to create a delegation to represent the opposition.

Global and regional powers recently met in Vienna and agreed on launching peace talks and a political process but there was no agreement on Assad’s role in that process.

Foreign backers of the warring sides disagree on whether the Syrian leader can stay in power during the transition process. The opposition is just as divided.

“The majority of the opposition believes Assad is part of the problem. There can’t be a solution unless he steps down immediately,” said Louay Safi, who was a member of the opposition delegation which attended the first peace conference held in Geneva last year.

Safi will attend the meeting in Saudi Arabia but he is no longer a member of the main political opposition in exile, the Syrian National Coalition.

‘Hostages of government’

The coalition will send delegates to Riyadh but so will the Damascus-based National Coordination Committee for Democratic Change. They are known as the tolerated opposition.

But many, like Safi, believe its members are hostages of the government.

“They are under the influence of the regime and they are scared of the regime. They cannot outright call for Assad’s departure.”

Politicians are not the only ones who do not see eye to eye. On the ground, armed groups do not share similar ideologies.

They have fought together on the front lines against the Syrian government and its allies. But apart from that, they lack a unified command, and have different visions for the country’s future.

One of the most powerful forces in Syria, al-Nusra Front, will not be present in Riyadh. It has been listed by the United States and the UN as a terrorist organisation and Syrian opposition politicians have urged the group to disassociate itself from al-Qaeda.

Until now, it has not. Its allies on the battlefield, though, will attend the meeting in Saudi Arabia.

“If everything goes well in Riyadh, some groups will distance themselves from Nusra,” Marwan Kabalan, a Syria expert, said. “There could also be a split within Nusra. Some may join ISIL and others may, for example, join Ahrar al-Sham.”

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Even if Saudi Arabia succeeds in getting the opposition to speak in one voice, some in the delegation may not be acceptable to Russia, the Syrian government’s main backer. Russia does not want to negotiate with groups such as Ahrar al-Sham and Jaish al-Islam, another powerful force based in the Damascus countryside.

For the opposition’s backers, however, they are the backbone of the armed rebellion.

Ahrar al-Sham is a powerful group with thousands of fighters and it will be represented in the Saudi meeting. The US has so far refused to work with it since it cooperates with al-Nusra.

“What is becoming clear is that whoever doesn’t support the Vienna process will be classified as terrorist organisations,” Kabalan said.

Jordan has been given the task of coming up with a list of groups deemed terrorist organisations. The ones on the list will not have representation at the talks and will not be part of any ceasefire deal.

And there are realities on the ground that could cause further conflict.

Omission of Kurds

While Syria’s Kurds will be represented, the exclusion of the PYD, YPG and SDF started causing tension even before talks in Riyadh started.

They are partners of the US in the fight against ISIL, but Turkey – a backer of the opposition – considers them terrorists. And some in the opposition accuse the PYD and the YPG of being allies of the Assad government.

We're not concerned with the output from the Riyadh conference and we will act like it never happened. PYD official

The PYD and the SDF – an alliance that groups the YPG with smaller Arab and Christian forces fighting ISIL with US backing – have decided to hold their own meeting in Hasakah to discuss “Syria’s future political system which must be decentralised as well as a constitutional solution for the national rights of the Kurdish people”.

“We’re not concerned with the output from the Riyadh conference and we will act like it never happened,” the PYD said.

“No one, whoever they may be, can impose on us any decision in which we did not take part.”

A party official told Al Jazeera that the exclusion is an attempt to weaken them at the behest of Turkey.

“We have already been attacked by opposition groups and we expect the violence to continue,” the official said.

“They should have invited all groups except ISIL and al-Qaeda offshoots or else the fighting won’t stop and Syria will be divided in the future.”

Lately, there has been fighting on some front lines in northern Syria between YPG and SDF and the Arab rebel groups.

This has not only complicated the battlefield but also the political landscape at a time the opposition is supposed to come together to present a united front.