No,it is not okay.Syrian hamsters have to be housed alone,and if it not will at some point cause severe injury or even death to one or all hamsters involved
Also it doesn't have to be bin cages.You can make all sorts of DIY cages,for example a potential idea would be a stacking square meter system could work too.Bin cages are very limiting,since you can't really increase the actual floor space easily and they're limited to under half a square meter which is far from ideal.