yes, very good question. As always, I like solving real world problems and hence will give my opinion here.

One thing you can do here is that categorize the project tracks and releases based on complexity. Obviously for the tracks which are complex it can be given to 1 project manager.

You have 25 tracks and 10 project managers.

• Make 1 project manager in charge of each track. So you have 1 face with customer
• Let 2 to 3 PMs manage the PMO and handle umbrella activities for the project.  Managing integration of tracks, dependencies, if any external co-ordination is needed, Change management , sharing knowledge between the releases , overall status reporting and risk , issue management etc. If these people can do a good job here then the overall project will be in control
• For releases or tracks where complexity is high , assign the remaining PMs and communicate the same to other stakeholders on the rationale behind assinging more than 1 PM> Also while assigning make sure you have clear roles and responsibility defined for each PM. 

The Sr. PM needs to focus only on the tracks where there are issues and let PMs handle other things. He can take weely stalk of the the tracks status.

Wow, 10 project managers are too many. I just don't know how big the project is. The bigger the project, the more manpower is required. - Steven C Wyer