The group, which owns restaurants, bars and nightclubs in Glasgow and Edinburgh, has courted controversy in the past with its treatment of its workers.
In August of last year, more than 30 of them took to Ashton Lane to protest over being underpaid by the company.
Representatives of Scots millionaire Stefan King agreed to hold talks with members of the Better Than Zero campaign following a slew of complaints from staff against the management of G1 venues.
Better Than Zero organiser Bryan Simpson said they had received complaints on a number of factors including pay being below the national minimum wage, gratuities being withheld for unfair reasons, and unpaid trial shifts.
Following the talks, which included STUC deputy general secretary Dave Moxam and Scottish Union Learning's Sarah Collins as well as representatives from Better Than Zero, including Mr Simpson, G1 have agreed to several conditions including new employment contracts, concessions on uniforms and training, no more punishments involving the keeping of gratuities or docking of wages and the adoption of a 'Tronc' system allowing staff to decide how their electronic tips should be allocated.
Mr Simpson told STV: "I didn't hold much hope for the talks as G1 Group has held our attention for the last 18 months.
"It's not just the largest hospitality firm in Glasgow but it's also among the worst - they have been fined twice for failing to pay staff minimum wage and have been the focus of our campaign from the outset.
"Complaints were so systematic - we had former workers come to us saying they had been treated unbelievably and had been forced out."
He continued: "The promise to abolish zero-hour contracts is a big symbolic one, and the tronc tip system is really good as well.
"This could be a future landmark for hospitality systems in Scotland."
Lesley Welsh, chief operating officer of G1, spoke to STV saying: "We are grateful to Better Than Zero to be recognised as the biggest hospitality company in Scotland and as a major influencer (sic) within the industry.
"The hospitality industry has come under criticism recently, however, the truth is that working in hospitality is not only fun but is rewarding and gives people great career opportunities.
"The meeting with Bryan and the Better Than Zero group was the first time we'd met so it's good to have had the chance to clear up misunderstandings and share our successful initiatives including employee contracts and the launch of tronc."