How do I make multi-mesh tileable textures?

Hi,

I am trying to make parts for a dynamically sized panel. The panel consists of corner, side and center parts (depicted in the image). All these parts should be tileable, which is where my problem starts. The project requires me to be hand painting the textures, therefore I am working in Substance Painter. I read much about tileable materials and how to unwrap models for them. But I am at a loss on how to transfer my knowledge to this case. Specifically on how to make multi-mesh tileable textures. If it matters for your answer, the blue lines connect sides, that should be seamless.

Just to emphasise: I am not looking for simple tileable textures, I am looking for tileable textures that work for multiple meshes.

If you have any advice, resources, tips or pointers, it would be highly appreciated!