two grid two bindingsource

Hi every body

i have two grid as master details. for example dgCar and dgCompany they are related as below:

bsCompany = new BindingSource(EntityCollection.CompanyEntity, "");
bsCar = new BindingSource(bsCompany , "CarEntity");

now in every row of master (Company)second grid shows related cars.

My problem is when i search special cars ,For example i search cars that name start with letter C:

in master grid should show companies that has searched cars(Start With C) and in details only cars that start with C

should show.How i could do it.

Thanks for any guides.

Regards

Ali