View attachment 44470
I used to build "Watergates" out of Hallmark card recorders, pocket memo minder recorders like the Memo Mate, or even ISD1000 chips from Radio Shack, sometimes I would retrofit other ISD based noise toys (most were at the time), adding in the recording and AGC components.
On the "Mic" input of the toy, I would add a 100k potentiometer from the high side of the radio volume control to ground, so the volume control of the radio would (should) have no effect on the volume that the recorder receives, independent of each other, center leg of the pot through a DC isolation capacitor, maybe a .01 uF (103) to a .1 uF (104) to the mic input of the board. .022 (223) or .047 (473) work good, too, higher value capacitors increase the lower frequency audio.
On the output side of the toy, use the same setup, in reverse. R1 is a load resistor, so the output of the toy "sees" the proper load of a speaker.
Optional, see if when the Play button of the toy is pushed, the SPK + and - lines on the toy have a nominal voltage, like 1.5v or 3v, this can be used to automatically "key" the PTT on the radio. R2 can be 1k to 4.7k, enough to turn Q1 on, any NPN switching transistor, like a 2SC945, 2N3904 or 2N2222, mind the pinout, 2SC945 has the Collector pin in the middle, instead of one of the side pins like the 2N transistors..