The German term "Beziehung" covers multiple aspects of relationship, and beside being the plural, "Beziehungen" has some additional meanings. However, while you might tell or guess an attitude towards somebody from a persons "Beziehung" to that other person, you would not denote it that way but would use "Haltung", "Einstellung", "Gesinnung", or "Verhalten":
...die Einstellung der christlichen Bevölkerung zu den Juden
indicates what the Christian population predominantly think about the Jews and their relationship towards them. This does not necessarily imply an interaction.
...die Gesinnung der christlichen Bevölkerung gegenüber den Juden
is a little bit outdated and only used in a highly formal context. It mainly signifies a basic moral, religious, and political position.
...die Haltung der christlichen Bevölkerung gegenüber den Juden
may already imply or include decisions how to act, e.g. to be solidary or not, and rather describes a current attitude as opposed to a general one.
...das Verhalten der christlichen Bevölkerung gegenüber den Juden
relates to the actual behaviour, including interaction.
"On the part of" is the equivalent of the German "seitens":
...die Haltung gegenüber den Juden seitens der christlichen Bevölkerung
The English and Yiddish sentence construction with "on the part of" would, however, be used only in a comparative context when also other groups would be involved, e.g.:
Die Einstellung der muslimischen Bevölkerung... Verändert hat sich jedoch die Haltung gegenüber den Juden seitens der christlichen Bevölkerung.
