How does your platform and solutions PMMs collaborate with product-focused PMMs?

This is a common model at enterprise focused companies. . I can share a bit from my experience at Microsoft and Qualtrics 

First- the industry PMM is the subject matter expert on that industry. They know the industry buyers, trends, competitive dynamics, pain points, use cases uniquely well. They are closest to the industry's customers, in-charge of those industry specific advisory boards and case studies, spend more time with industry specific sales teams (assuming there is some specialization there). The entire company needs to recognize this expertise

Second- we built deep collaborative working sessions between industry PMMs and core product PMMs. Goal is for industry PMMs to understand product specific messaging/positioning/value prop/differentiators as well as an in-depth walk through of all messaging assets (pitch decks, demos, web pages etc.) by the PMMs. This would happen over a few sessions. 

These two pieces above- industry expertise and a depth understanding of product messaging- allowed industry PMMs to build the industry specific version of the solution messaging. And also identified the gaps in the solution storytelling (e.g. case studies, solution demos etc.). They would then work with the right teams to fill those gaps.  

We created multiple informal collaboration points between the two teams for proper knowledge transfer, mutual respect and feedback on each other's work. But most importantly - we gave the industry PMMs the full autonomy to own the assets for their audiences.

• Regular catch-ups (1-on-1s): These are important opportunities for specific line-of-business (LOB) / product leads to share top priorities & initiatives with those who operate more cross-functionally across PMM, and vice versa. In addition to 1:1s, these can also be in the form of quarterly roadshows between partnering teams. 
• Regular readouts (1-to-many): Whether its giving visibility into the planned campaign calendar, or sharing recent research, finding a cadence and channel to regularly socialize the work being done across different teams within PMM helps cross-polinate ideas. These readouts serve as springboards to ensure consistency, optimize / expand on existing efforts, while avoiding duplication. 

TL;DR: It's a two-way street. Make a conscious effort to get plugged in. 

For every product launch, consider which solutions/segments to whom it's particularly applicable and invite those counterparts to share input as subject matter experts. 

In a similar vein, PMMs who work more horizontally across product marketing should proactively be plugging themselves into launch & campaign calendars to capitalize on the right opportunities and marketable moments. Challenge teams to be specific about the type(s) of good fit customers so you can tailor use-cases and examples to ensure positioning is even more relevant.