Combining Inputs and Offsetting by Separate Grounds

Greetings,

I'm not really sure about the subject line if it's right or not, but it's basically what I'm looking to do.

I posted just yesterday a question about a circuit which was answered very well by one T. Wescott. It turns out I simplified the problem too much and a better representation is as follows.

Given inputs (P0, P, Q0, Q, R0, R)

P0 GND P > P0 Q0 GND Q > Q0 R0 GND R > R0

And constants (A, B, C)

A constant < 1 B constant < 1 C constant < 1

Desire these outputs:

P* = A(P - P0) + B(Q - Q0) + C(R - R0) + P0 Q* = A(P - P0) + B(Q - Q0) + C(R - R0) + Q0 R* = A(P - P0) + B(Q - Q0) + C(R - R0) + R0

Note that the operation is the same other than adding a different offset for each output.

Is there a simple solution for this? (e.g. just resistors)? Is there a systematic way to scale up to more and more inputs and constants? e.g. S0/S/D, T0/T/E, etc.

Any references on-line or otherwise are welcome. Any searches I do bring up operational amplifiers which might be overkill for this kind of application. And any searches I do regarding resistor circuits don't seem to go beyond elementary introductions.

Thank you for reading.

Regards,

YR