The option of switch on the handgrip is not possible for your connectors.
However, you can replace the inlets with the type E 50. The construction size and confirmation is exactly the same as your current inlets. You do not need to drill or take other architectural facilities.
For inlet type E 50 See: https://www.snoek.com/webshop/inlaat-compleet-c-110_112_187.html
For associated hoseset see: https://www.snoek.com/webshop/zoekt-slang-schakelaar-c-119_123_135_155_178.html
For further information, you can also contact the sales department
Tel. : 0345 599360
Fax. : 0345 599758