3 point seat belt retrofit

[FDN850HU]

Hi all, it seems i am unable to find seats with 3 point belts on them, so i was thinking about buying automatic 3 point seat belt sets and try to find a place on the chassis to attach them and then i can use my original seats (those have 2 point belts only) Can i do this onto the c pillar? Has anyone done such? If i am wrong, which way should i do it? Tia

[dumper]

Have looked at minibus/ crew cab van in breakers yards the 3 point belts fit the shoulder in the top of the seat