How to create an agile team in a big organization that is used to working in waterfall.

So the default way for our organization to work is that the architects and PMs plan tickets weeks and months in advance, and then treat every developer as a separate production line. Each developer gets assigned a ticket, and then the developers go away and work alone for days, if not weeks.

Me and 3 other infrastructure/devops-guys/gals in the company got sick of it so a year ago we formed semi official infrastructure/dev-ops team. But it feels like we are trying to swimming upstream the waterfall and drowning.

The biggest problem right now seams to be that in order to take ownership of our planning process we have to produce a 6 week plan. and given the workload we have don't have the time to plan, break down the plan into tickets, estimate every ticket and assign ticket to each person 6 weeks into the future. And if we fail to do that then the project managers will create a plan for us that usually involves us 4 working on 4 different projects in parallel for thous 6 weeks. witch tends to effectively splitting up the team.

I don't have any specific question other then, do you have any words of wisdom for us other then "quit".