How can I split a periodic signal?

I'm receiving a phase modulated signal representing a periodic pulsed byte that looks something like this:

-------------|-|||--||-------------|||--||||-------------|--||||-|-------------

I'm trying to understand how I might split this signal roughly halfway between each pulse of activity so I can save each pulse as a separate IQ fil, bit like this:

------|-|||--||------

-------|||--||||-------

------|--||||-|------

The split does not have to be precise, it only needs to avoid bisecting any of the pulses. Here are some things I've tried.- Creating a custom block on the receiver that uses a timing interval. Unfortunately, the pulses aren't perfectly periodic so eventually this causes the split to drift.

- Since I also control the transmitter, I tried sending an async pmt message from the transmitter to the receiver, but again, since the message is async the timing is too unpredictable to make an accurate enough cut.

- I was also wondering if there is any way to propagate a tag from a transmitter to a receiver if both are in the same flow graph, but I couldn't find any info on how to do this.

Any Ideas? Thanks!