[LAD] Midi Channel routing with hardware?

Hello list, tl;dr: Is there a cheap midi hardware that just gets midi information in and routes it out, except on a different, single, channel which I can change easily up and down directly on the hardware? Long version: Recently my master keyboard broke. It was just a cheap, used m-audio keystation 49e. I did not buy a new master-keyboard because I have a Roland HP207e digital piano here which is vastly superior when it comes to actual playing. Sadly not to control midi data. I have a Behringer BCF2000 here which I connected to my keyboard now, so I should be able to do something with it, but there is one thing missing: Channel Changes. Anybody who worked with Linuxsampler knows that channel switching is very important to switch instruments, while program changes are neglectable. So maybe there is a way to use my piano, which always sends on the first channel (except I dive into inaccessible menus) if a) I find a way to shortcut the "change channel" command, but I don't know how. It has midi in and a usb connector, but that is not used to control it, just to send and receive midi data. Incoming data gets interpreted like a sampler does. b) There is a way to use my BCF2000. I am very inexperienced with that thing. c) There is a cheap standalone hardware, just a "little box", I can plugin between my linux box and the piano, which re-routes the midi data, like I mentioned in the short version above. d) I build something myself, a small linux plug computer where I somehow attach two buttons (ch up and dow) and use the usb connections. At least the cables are cheaper :) But this is the most unrealistic method, although it might be the most interesting one. Maybe you know something? Nils P.S. I know I can do the channel routing directly on my linux computer, after receiving the data and before sending it to a sampler. But that is inconvenient.