As activate footswitch in specific parts of a COMBI?

[ACRIS]

Hi,
I would like to see if I can help with a problem I have.
I need to control with a foot switch a delay effect in an area of a COMBI. The COMBI is divided in piano and organ, and I need to activate delay effect a on the piano and not in the organ.

My idea was:
In MODE GLOBAL / P2 CONTROLLERS/ FOOT SWITCH ASIGGN: RT KNOB 1B.
In the COMBI / P1 CONTROLLERS / KNOBS 1B: MFX SEND 1.
In P9 MFX- TFX / MFX1: STEREO BPM DELAY.
In P5-1,2 MIDI FILTER 1,2: Check only the boxes of the instrument that will have the effect (piano).
However pressing the foot switch is actuated delay in the organ and piano, (it which is it not desired).

As additional data:
In P8-1 IFX, I have assigned to the organ IFX1 ORGAN VIB/CHORUS chained with IFX2 ROTARY SPEAKERS OD (and with the foot switch sounds the delay, which should not happen).
If I put the route in L / R with the foot switch does not active the delay of the organ (which is what I need). But these effects are very necessary for the organ.

Would greatly appreciate if someone can tell me how I can achieve with a foot switch assign a effect delay to the piano but not in the organ, but using the necessary effects of the organ.

Greetings, thank you very much.
sorry for my bad English.

[SanderXpander]

I would set the foot switch just to foot switch in both global and the combi. Then make sure only the piano is going to the delay bus (mfx send), and use the foot switch to control the wet/dry level of the delay (ams).

[ACRIS]

Thank you SanderXpander, I help myself very much your response.