best practice mdi app

Hi

I have a class OgreForm.cs Another class say RightSidebarProperties.cs, another one LeftSidebarProperties.cs. Then Mainform.cs that is responsible in creating all 3 forms and holding them.

OgreForm.cs have data that needs to be use in the other form classes, likewise the other form classes have data that OgreForm.cs needs as well.

I was wondering what's the best practice here, do I pass around the class as parameters to each other? So RightSidebarProperties have both OgreForm.cs and LeftSidebarProperties.cs instance?

Just could not get my head around this.

Thanks for your insights.