I'm trying to build a RNN model for predicting an arterial blood pressure (ABP) time series based on two other time series, namely, ECG and PPG time series.

I'm able to build fairly good models based on LSTM's and GRU's to perform this task for a single patient, that is, given two time series (ECG and PPG) I'm able to predict a third time series (ABP).

However, my current objective is to take several sets of ECG and PPG time series (each one corresponding to a different patient) and predict the ABP of a patient that is not in the mentioned set. 

So, to make myself clear, I have 10 sets of time series of the kind [PPG, ECG, ABP] and I have an 11th set of the kind [PPG, ECG]. My wish is to obtain (predict) the ABP time series of the 11th set.

Hope everyone can understand my problem and someone can help me.

Thanks in advance!