BGP Route Signaling to another router

Hoping someone can explain a possible solution. I currently have this type of setup:

R1=isp1 R2=isp2

R1 and R2 both advertise /24 to the internet via eBGP

R1 and R2 both have iBGP session

R2 has ebgp with Route Reflector. Route reflector sends bgp update with community string but the update is intended for R1 to pull the advertisement from the internet based on the top and Route maps configured.

How can I pass this update through R2 ensuring R2 doesn’t act on the update but simply passes the update to its iBGP neighbor (R1 in this case)

Unfortunately it doesn’t allow me to post a diagram hence have to explain in text.