Thank you for writing.
There is no way to have more than two filters with the default filter dialog. Do achieve that, you need to remove the menu item which opens the default dialog from the context menu and add you own menu item there. Then create your own form with the desired filtering functionalities and open it upon clicking your item.
Here are some articles which you might find helpful:
I hope that you find this information useful. Let us know if you have any other questions.
All the best,
the Telerik team