Exceptional but possible.
The Singapore Court of Appeal has taken the rare step of holding that the step of one defendant in proceedings was to be attributed to a co-defendant who had not even been served with the statement of claim. That step was filing an application to strike out proceedings on the merits with the effect of disentitling both the applicant and the un-served co-defendant from applying for a stay in favour of arbitration under s 6(1) of the International Arbitration Act.
The court found that the un-served co-defendant had the real interest in the application, greater than the interest of the applicant which was controlled by the co-defendant and was only a shell company. The relief in the application was sought on behalf of the co- defendant.
While it would only be in exceptional circumstances that the court would attribute an application taken up by one defendant to a co-defendant, those circumstances pertained in this case.
Read the full head note here:  FICR 11.