If you are wanting to split a single characteristic into two separate notifications, I would be doubtful there is a way to do that
But, if you just want your data in to separate notification packets, then you could probably setup your sending-server to send two different notifications (say NTF1 and NTF2) that would each contain part of the data. Then, you merely send a notification with the NTF1 half, and send a NTF2 half afterwards, rebuilding the original characteristic/data on the receiving side. This would require two separate characteristics unfortunately, but would allow you to differentiate between the first and second half of the data.
The other option, is to send both notifications on the same characteristic you have right now, and then to receive and store the notification data into the reassembled packet. This might overwrite your original characteristic however.
e.pratt_1639216 Hello, do you have any example on how to build this?
"But, if you just want your data in to separate notification packets, then you could probably setup your sending-server to send two different notifications (say NTF1 and NTF2) that would each contain part of the data. Then, you merely send a notification with the NTF1 half, and send a NTF2 half afterwards"
Unfortunately, I don't have an example of this, but it would be the same theory/practice as dealing with IP Fragmentation (IP fragmentation - Wikipedia )
You essentially take your data, and instead of trying to send it all at the same time, you send part of it in each packet, and the receiving side then sorts and recombines the data for use.
To send the "long" data of 0xAA,0xBB, you would send a notification with
0x01, 0xAA to signify the first section of data is 0xAA (0x01 is for the receiving side to reorder the packets)
Next you would send a packet with 0x02, 0xBB to signify the second section of data is 0xBB (0x02 is for receiving side to reorder the packets)
The receiving side would need to do alot of work to deal with missing packets of data, and verifying all of the data is present before using it. But it should be feasible with a little bit of trial and error on the exact sequencing/data formats.
You will probably need to have some way to signal a retry of the notification, how many packets of data/notifications you expect, and all data received for use.